sustainability

Article
Construction Process T echnical Impact Factors on
Degradation of the External Thermal Insulation
Composite System
V irgo Sulakatko 1 , 2 , * and Frank U. V ogdt 2
1
Department of Civil Engineering and Architectur e, T allinn University of T echnology , 19068 T allinn, Estonia
2
Institute of Civil Engineering, T echnical University of Berlin, 10623 Berlin, Germany; [email protected]
* Correspondence: vir [email protected]
Received: 16 September 2018; Accepted: 20 October 2018; Published: 26 October 2018
    
  

Abstract:
The Eu rop ean clim ate stra tegy has en courag ed the usa ge of the Ext ernal Th ermal
Insu lation C omposi te System ( ETICS) t o incr ease th e ener gy eff iciency o f extern al build ing enve lopes.
This e xterna lly and r elat ively ea sily appl icable f açade so lution m ust meet v arious te chnica l
r equir eme nts. This p aper dev elops a tec hnical s everity e valuat ion mode l of on-sit e constr uctio n
acti vities o f ETICS to pr ioriti ze the ris ks of the con struc tion pr oces s. The mo del can be u sed
inde penden tly by any s takehol der of the c onstr uction p ro cess. The r elev ance of th e activi ties is
asse ssed wit h the Fail ure M ode Effe cts Analy sis meth od. The mo del weig hts the imp act of the e ssenti al
tech nical r equi re ments and s imulat es an inte grated we ighted t echnica l severi ty value , whic h is deriv ed
fr om the a nalysis o f expert s’ judgm ents val idated wi th the non -param etric Fr iedman’ s test. The data
coll ection f or pr obabil ity of occu rr ence and di fficul ty of dete ctabili ty follo ws the Delp hi techn ique to
quan tify the o pinion s of a gr oup. The si mulati on, cond ucted on 1 03 degrad ation fa ctors, s hows that
the on -site co nstru ction ac tiviti es of ETICS s tr ongly inf luence t he decr ease i n the tech nical r esil ience
of lon g-term d urabil ity , mech anical r esi stance , and stabi lity , as w ell as the a bility to b ypass te nsions .
The hi ghest ri sk is detec ted by the s hortco mings in th e layers o f substra te, r einfor ce ment, adh esive,
and ad dition al detail s.
Keywords:
External Thermal Insulation Composite System; ETICS; quality contr ol; durability;
building defects
1. Introduction
Eu r op ea n co un tr ie s ne ed t o r ef ur bis h ex is ti ng d we ll in gs a nd i ncr ea se t he ir q ua li ty as w el l as e ne r gy
ef fi ci en cy , as 7 0% o f th e ho us ing s to ck i n th e Eu r op ea n Un io n wa s bui lt b ef or e 19 80 [
1
]. It i s ex pe ct ed
th at t he l if e- sp an f or m ul ti -s tor y dw el li ng s is b et we en 5 0 an d 70 y ea rs, w hi ch e mp ha si ze s th e ne ed f or
im mi ne nt u pd at es . Th e en er gy ef fi ci en cy r eq uir em en ts h av e in cr e as ed th e us ag e of t he E xt er na l Th er ma l
In su la ti on C om po si te S yst em ( ET IC S) a s a r ef ur bi sh me nt p oss ib il it y to e xt en d th e se rv ice l if e of t he
ex te rn al s he ll [
2
,
3
]. Du e to t he i nc r ea se d in te r es t in t hi s con st r uc ti on te ch no lo gy , th e du ra bil it y of t he
ET IC S, a s we ll a s th e pa th ol ogy o f th e de gr ad at io n si gn s, ha s be co me a p op ul ar r ese ar ch s ub jec t.
The ETICS has many advantages, which have made it a favourable façade solution and incr eased
its usage in European countries. This complex system is a combination of differ ent construction
materials in several layers, all having specific r equirements as well as application methods. Each layer
of the system is designed to provide particular value and has a significant r ole. Possible deterioration
causes include poor design, unsuitable usage of building materials, or on-site construction technology
inadequacies [
4
]. Institut für Bauforschung [
5
] r evealed in their study that construction activities
cause 66% of the defects in the ETICS, which have failed to achieve ener gy performance requir ements.
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Sustainability 2018 , 10 , 3900 2 of 26
Neumann [
6
], in turn, stated that three-quarters of the on-site activities ar e avoidable. These statements
raise the question as to why the number of occurring defects is so high, as the r elevance, as well as the
main causes of degradation, ar e known to the industry .
Cons truct ion infl uences t he re silien ce as well as t he futur e det eriorat ion of the E TICS in ea ch
laye r . As each la yer has a di ffer ent pur pose, the r elevanc e to the sys tem is div erse. T he re sear ch
cond ucted in t he field o f the quali ty of the ET ICS rati onaliz es the spec ific r eason s for degr adatio n in
silo s. These s ilos have c aused a si tuatio n wher e a lar ge numb er of r easons f or degrad ation ha ve been
iden tified , but it is imp ossibl e to prior itize the ir impac t on the ETI CS syste m as a whole . Amar o et al. [
7
]
and Si lva [
8
] appr oac hed the pr obl em fr om the mai ntenan ce point of v iew , dev elopin g a pre dictive
main tenanc e assess ment mode l. Their top -down ap pro ach dete cts dete riorat ion and con nects mu ltiple
poss ible cau ses. T o investi gate the c ause for v isible d eterior ation wi th in situ a nalysi s, a destr uctive
test i s most oft en re quir ed. A num ber of con ducted d estru ctive te sts have be en discu ssed [
6
,
9
,
10
],
as wel l as r econstr ucted in la borator y condit ions [
11
–
13
]. Ad ditiona lly , the behav ior of dev iation s
of spe cific co mponen ts has been s tudied i n isolat ion, whic h determ ined the p atholog y ro utes to
cons ider . Th ese r outes in clude th e change in m echani cal pr opert ies thr ough a dded knea ding wat er
to the m ixtur e [
14
], fr eezing o r drying o f the mixtu re ca used by we ather ef fects whi le the faç ade is
insu fficie ntly cov ere d [
12
,
14
,
15
], incr eas ed vapor r esi stance d ue to incr eas ed thickn ess of the m ortar [
16
],
or inc re ased ther mal cond uctivi ty thr ough th e gaps bet ween ins ulatio n materia ls [
17
]. Thes e and many
othe r degrad ation fa ctors ar e inc luded in ou r study in a sin gle fram ework to en able the s etting o f
prio rities d uring th e constr uctio n pro cess.
The r esearch pr oblem is approached using the developed technical r elevance model, which
follows the method of Failure Mode Ef fects Analysis (FMEA) and is suitable for use in small and
medium enterprises (SME), who ar e the main performers in this industry . The method quantifies the
technical severity and considers the dif ficulty of detectability as shortcomings occur and the probability
of occurr ence [
18
,
19
]. Although this approach is most often used for pr oduction, the method has also
been r elevant in the construction industry [
20
,
21
]. The method is not flawless and has been criticised
due to the mathematical model by Puente [
22
] and Bowles [
23
]. They argued that as the occurr ence
and detectability factors ar e linear , their effect might be overrated in comparison to the technical
severity . Pillay and W ang [
24
] impr oved the model with a weighting factor to balance the subjective
evaluations. Researchers even included various other factors in the model to pr ovide more specific
r esults according to their r esearch goals [ 25 , 26 ].
The ma in aim of th is re sear ch was to d evelop an a ssessm ent model o f the shor tcomin gs that
quan tify the o n-site d egradat ion fact ors of the ET ICS usin g the FMEA m ethod [
27
] for SM Es. T o ac hieve
this , we devel op a sever ity weigh ting sys tem acco rdi ng to the es sentia l req uir ements s et for the f açade
syst em and int egrate it i nto a tech nical r elev ance ass essment m odel. The r esults ar e pres ented by t he
sequ ence of th e constr uctio n pro cess as in dividu al compo nents, a s well as the f inal out put—te chnica l
risk p riorit y number ( TRPN). Th e develo ped tool en ables cl ients, s upervi sors, and c ontrac tors to fo cus
thei r attent ion on the m ost r elevan t on-site a ctivit ies to incr ease the qu ality of t he ETICS an d their
bene fits. The as sessme nt of the im pact fact ors diff ere ntiate s the high- risk act ivitie s during co nstr uction.
2. Materials and Methods
The de velope d technic al re levanc e model ev aluates t he on-si te degra dation fa ctors of t he ETICS
and is s uitabl e for SMEs wh o have a lim ited num ber of expe rts. The r ese arc h design i s divided i nto
six ph ases (Fi gur e 1 ). The mo del can be f ollowed b y indivi dual com panies to c alcula te firm- specifi c
risk s as const ructi on pr oducts a re im pro ving rapi dly and ne w constr uctio n technol ogy is con stantly
emer gin g. T o st art, the s cope of th e model and l imitat ions wer e set ( Step 1), f ollowe d by the sel ection
of exp erts (St ep 2) and de velopme nt of the qu estion nair e (Step 3) . The da ta colle ction an d analysi s
wer e divi ded into t wo sets of ex perts’ j udgemen ts due to th e differ enc es in the nat ure o f the data .
The ev aluati on of tech nical asp ects r equir es in-dep th knowl edge and un dersta nding of t he façad e
syst em (Step 4 ). The occu rre nce rati o and dete ctabili ty of the sh ortcom ings is mo re r egio n-, comp any-,

Sustainability 2018 , 10 , 3900 3 of 26
and cr aftsme n-spec ific and co ncerns t he for ecast ing as wel l as practi cal expe rience ( Step 5). The tec hnical
risk i s calcul ated as th e conver ged v alues ar e est ablish ed (Step 6 ).
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( S tep 4 ). The o ccurr ence rat i o an d de tecta b i l i ty o f the s hor tco mi ng s i s mor e regi o n - , co mpany - , a nd
craftsme n - speci fi c an d co ncerns the fo rec asti ng a s wel l as pr actic al ex per i ence ( S tep 5) . The techni cal
ri sk i s cal cul at ed a s the co nv erge d value s are est a b l i shed ( S tep 6 ) .

Figu re 1 . Res ea rch de si gn fo r the technica l rel eva nce mo del .
2 .1 . S tud y Scop e and L imit at ions
The data co l l ecte d to test the si mul at i o n mod e l concer n ed the ETIC S wi th the fol lo wi ng
cha r acteri sti cs , w hi ch are c o rre spo ndi ngly the l i mi ta tions o f data co l l ectio n : the s ub j ect is a n e x i sti ng
mul ti - apa rtme nt bui l d i ng; ex tern al w all s are m ade o u t o f maso nry o r pre fa b ri cat ed co ncrete pa nel s;
the fi x i ng method fo r the E TICS i s e i ther pure l y b o nded wi th adh esi v e o r mech a ni call y f i x ed wi th
an c hor s a nd suppl emen ta r y adh e si v e; rei nfo rce ment c o n si st s o f a mi x t ure an d gl a ss – fi b er mes h; the
therm al i nsu l at i o n pr o duct i s c o mpo sed of mi neral w o ol o r ex pan de d po l ysty rene wi th a thic knes s
o f 150 mm to 2 50 mm ; an d the study co ncerns t he regi on - speci f i c as pec ts o f Esto nia , wh i ch l i e s i n the
Dfb (s now c l i ma te, ful l y hum i d, warm su m mer) zone a cco rd i ng to the Köp pen - Geiger M ap.

Figure 1. Research design for the technical r elevance model.
2.1. Study Scope and Limitations
The da ta colle cted to te st the sim ulation m odel con cerned t he ETICS w ith the fo llowing
char acteri stics, w hich ar e corr esp ondingl y the limi tation s of data col lectio n: the subj ect is an ex isting
mult i-apar tment bu ilding; ex ternal w alls ar e made ou t of mason ry or pr efabr icated c oncr ete pan els;
the fi xing met hod for th e ETICS is e ither pu rel y bonded w ith adhes ive or mec hanica lly fixe d with
anch ors and su pplemen tary adh esive; r einf or cement co nsists o f a mixtur e and g lass–fi ber mesh ;
the th ermal in sulati on pr oduct is c ompose d of miner al wool or ex panded p olysty ren e with a thi ckness
of 150 m m to 250 mm; a nd the stu dy concer ns the r egion -speci fic aspe cts of Esto nia, whi ch lies in t he
Dfb (s now clim ate, ful ly humid, w arm summ er) zone a ccor ding to t he Köppe n-Geig er Map.
2.2. Identification and Selection of Experts
Ther e is no quantified data available on the resear ch subject. Hence, expert judgement was
suitable for use in this study . The selection of experts considerably affects the quality of the data [
28
].

Sustainability 2018 , 10 , 3900 4 of 26
The terms for the selection of experts was their in-depth knowledge and understanding of the
technical considerations of the ETICS as well as practical on-site experience. According to Olson [
29
],
variations in r eviewer backgrounds ar e allowed. Hallowell et al. [
30
] suggested that in the construction
industry , expert identification could be conducted thr ough the membership of nationally recognized
committees or by participation in similar studies. The expert should meet at least four of the following
r equirements: (1) at least five years of professional experience in the constr uction industry; (2) tertiary
education degr ee in the field of civil engineering or other related fields; (3) pr ofessional registration
in the field of construction; (4) member or chair of a nationally r ecognized committee for the ETICS;
(5) writer or editor of a book or book chapter on the topic; (6) faculty member at an accr edited
institution of higher learning; (7) invited to present at a confer ence on the topic; and (8) primary or
secondary writer of at least thr ee peer-r eviewed journal articles.
As t he m od el w as d ev el op ed f or u sa ge in S ME s, t he n um be r of r e qu ir e d ex pe rts w as s ma ll . The m os t
su it ab le n um be r of p an el ist s ha s no t be en e xa ct ly d ete rm in ed i n th e li te ra tu r e to qu an ti fy t he e xp er ts ’
ev al ua ti on s. Th e si ze o f th e gr oup d ep en ds o n th e av ai la bi lit y of t he e xp er ts , av ai la bl e r es ou r ce s,
an d r es ea r ch t op ic [
31
]. In o th er s tu di es o f th e con st r uc ti on i ndu st ry , a s ma ll n um ber o f ex pe rt s wa s of te n
us ed . C ha n et al . [
28
] in vo lv ed e ig ht p an el is ts to s tu dy t he s el ec ti on p r oc ess o f a pr oc ur eme nt s ys te m in
th e co ns tr u cti on i nd us tr y . Ch au [
32
] in cl ud ed s ev en e xp er ts t o ev alu at e th e es ti ma te d pr oba bi li ty o f un it
co st s. Si x ex pe rt s we r e id en ti fie d an d se le ct ed f or a r is k as ses sm en t of r oa d pr o je cts [
33
] an d fi ve e xp er ts
ev al ua te d co ns tr uc ti on b us in es s ri sk s [
34
]. S tud ie s ha ve i nc lu de d 3– 14 4 ex pe rts i n th e st ud ie s of v ar io us
in du st ri es [
35
] an d 3– 93 p an el is ts i n th e co ns tr uc ti on i nd us tr y [
31
]. Ha ll ow el l et a l. [
30
] pr op os ed a p an el
si ze b et we en 8 a nd 1 2, w he r ea s Ro we et a l. [
36
] su gg es te d in cl ud in g fi ve or m or e ex pe rt s in t he pa ne l an d
po in te d ou t th at t he r e ar e “no c le ar d is ti nc ti on s in p ane l ac cu ra cy ” wh en t he p an el s iz e var ie s fr om 5 t o
11 e xp er ts . H en ce, f or t he u se r of t he m od el , at le as t fi ve e xp er ts s ho ul d be in cl ue d.
T o test the developed technical severity evaluation model, 14 experts with the r equired
characteristics wer e identified through nationally r ecognized ETICS committees in Estonia and
Germany who agr eed to participate in various phases of the study . The panel included seven
experts each fr om Germany and Estonia. Seven of them wer e consultants/supervisors, two were
managers/pr oject managers in façade construction companies, and five were technical specialists
fr om ETICS manufacturers. T wo of the experts pr e-tested the questionnaire and 12 out of the 14 wer e
involved in the judgment of technical severity in 2016. The demographics of the experts participating
in the technical severity evaluation ar e shown in Figure 2 .
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2 . 2 . I d entificatio n and Sel ectio n of E x p er ts
T here i s no quan ti fi ed data a vail ab l e o n t he rese arc h su b j ect . He nce, exp ert j udgement w as
sui table fo r use i n this st ud y. The sel ecti o n o f ex per ts co nsid erab l y affec ts the q ua l i ty o f the dat a [2 8 ] .
The terms fo r the sel ecti on o f ex per t s w as thei r i n - de pth knowl ed ge a nd un de rsta ndi ng o f the
techni cal co nsid erati o ns o f the ETIC S as wel l as prac ti cal o n - si te ex per i ence. Ac cord i ng to Ol son [2 9 ] ,
vari at i o ns i n revie wer b a ckgro und s are all o wed. Ha l l o well et al . [3 0 ] sugg ested th at i n the
co nst ructi o n i ndustry , e xpe rt i de ntifi catio n co ul d b e co nduc ted thro ug h t h e mem b ers hi p o f
na ti o na l l y rec o gnized co mm i ttee s o r b y parti ci patio n i n si milar studi es. The ex per t shoul d meet at
l east fo ur o f the fol lo wi ng requi rements: (1 ) a t l ea st fi v e years o f pro fe ssio na l ex per i ence i n the
co nst ructi o n i ndustry; (2 ) t erti ary ed ucatio n de gree i n the fi el d o f c i v i l engi neering o r o ther rel at ed
fi e l ds; (3 ) p ro f essi o na l reg istra ti o n i n the f i e l d o f co nst ructi o n; ( 4 ) m emb er o r ch air o f a na ti o na l l y
rec o gnized co mm i ttee f o r t he ETIC S; (5 ) w ri ter o r edito r of a b o o k o r b o o k cha pt er o n the to p i c; (6)
f acult y me m b er a t a n accre di ted i nst i tution o f hi gher learning; (7 ) i nv i ted to pre s ent a t a co nfer ence
o n the to pi c ; an d (8 ) p r i ma ry o r se co nda ry wri ter o f at least t hree pee r - revie wed j ourna l arti cl es .
As the mod el wa s de v el o pe d fo r usag e i n SM Es , the numb er o f requi red ex per ts w as sm all . The
most sui table numb er o f pan el i sts has not b ee n exactl y de termi ned i n the li terature to qu an ti fy the
ex per ts ’ e v alua ti o ns. The s i ze o f the gro up de pends o n the a v ail a b i li ty o f the ex per ts, a vail ab l e
reso urce s , an d rese arch t o p i c [ 3 1 ] . In o ther studi es o f t he co nst ructi o n i ndustry , a sma l l numb er of
ex per ts w as o fte n used. C h an et al. [2 8 ] i nv o l v ed ei gh t pan el i sts to study the sel e cti o n pro cess o f a
pro cure ment sy stem i n the co nst ructi o n i ndustry. Chau [3 2 ] i ncl uded sev en e x pe rts to ev alu at e the
esti ma te d pro ba b i li ty o f unit c o sts. S i x ex per ts were i d enti fi ed an d sel ecte d f o r a r i sk as sess ment o f
ro ad pro j ects [3 3] an d fi v e ex per ts e valuated co nst ruct i o n b usi ness ri sks [3 4 ] . Stud i es ha v e i ncl uded
3 – 1 44 ex per ts i n t he studi es o f v ari o us i ndustri es [3 5 ] an d 3 – 9 3 pan el i sts i n the co n structi o n i ndustry
[3 1 ] . Ha l lo well et al. [3 0 ] pr o po sed a pan el si ze b etween 8 an d 1 2 , wh ere as Rowe et al. [ 3 6 ] sugg ested
i ncl ud i ng fi v e o r mor e ex p erts i n the pan el an d po i nt ed o ut tha t there are “ no c lear di sti nctions i n
pan el accu r acy” wh e n the pan el si ze vari es fr o m 5 to 1 1 ex per ts. Hence, f o r the u ser o f the mod e l , at
l east f i v e e x per ts shoul d b e i ncl ued .
To test the de v el o pe d tec hn i cal sev eri ty eval ua ti o n mod el, 1 4 ex per ts wi th the requi red
cha r acteri sti cs were i de ntif i ed thro ugh nati o na l l y re co gnized ETIC S co mm i ttees i n Esto ni a a nd
Germ any w ho ag ree d to pa rti ci pate i n v ari o us ph as es o f the study. The p a nel i ncluded sev e n e x per ts
each fr o m Ger m an y a nd Esto ni a. Se v en o f the m were co nsu l ta n ts/super vi sor s, two were
manage rs/p ro j ect ma n ag er s i n façade co nst ructi o n c om pa ni es , an d fi v e were te chnic al speci al i sts
fr o m ETIC S ma nufact urer s . Two of the ex per ts pre - tested the qu esti o nn air e an d 1 2 o ut o f the 1 4 were
i nv o l v ed i n the j udgment o f techni cal sev eri ty i n 2 016 . The de mograp hi cs o f the ex per ts parti ci pating
i n the techni cal sev eri ty e va l ua ti o n are shown i n Fi gure 2 .

Figu re 2 . Demo gr a phics o f the exper ts par tic ipa tin g i n the tec hn ical sever ity evalu a tio n. ETICS =
Extern a l Th e rma l In sula tio n Co mp o site System .

Figure 2.
Demographics of the experts participating in the technical severity evaluation. ETICS =
External Thermal Insulation Composite System.
As the study aimed to identify the situation in Estonia, the Estonian experts were asked to
participate in the r egion-specific data collection. Five of the seven Estonian experts agr eed to participate

Sustainability 2018 , 10 , 3900 5 of 26
in the survey conducted in 2018. All of them had 10 to 20 years of practical experience in the field.
Figur e 3 visualizes the demographics. All the data were collected during face-to-face meetings due
to the r equirement of a high r esponse rate. Due to the small panel size of the region-specific data
collection, it can be argued that the full capacity of the Delphi technique was not fully used. As the
quality of the expert panel is mor e significant than the size [
37
], and since the aim of the study was to
test the developed model, the small panel size in the Delphi study was satisfactory .
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As the stud y aim ed to i den ti fy the si tua ti o n i n Esto ni a, the Esto ni a n ex per ts were asked to
parti ci pate i n the regio n - speci f i c data col l ect i o n. Fi v e o f the sev en Esto ni an e x per ts ag ree d to
parti ci pate i n the surv e y co nducted i n 2 0 1 8. A l l o f them h ad 1 0 to 2 0 years o f pra cti cal ex per i ence i n
the fi e l d. F i gure 3 v i sua l i z es the de mogra phi cs. All the data were co ll ecte d duri ng face - to - face
meeti ngs due to t he requi r ement o f a hi gh respo nse r at e. Due to the s ma l l pan el si ze o f the re gi o n -
speci fi c data co l lectio n , i t can b e ar gued t hat t he ful l c apa ci ty o f t he Del phi tech n i qu e w as not ful l y
used. As the qual i ty o f th e e x per t p an el i s mor e si gnifi c an t t h an t he si ze [3 7 ] , an d s ince the aim o f th e
study w as to test t he de v el o ped mo del, the sma l l pane l si ze i n the Del phi study w as s at i sfactor y.

Figu re 3 . Demo gr a p hi cs o f the exper ts pa rticipating in the oc cu rr ence and detect a bility evalu a tio n.
2 . 3 . Sel ection o f D egrad at ion Fact ors
The l i st of de grada ti o n facto rs was co ll ecte d thro ugh a l iterature re v i ew . The l i st of shortco mi ngs
i s b as ed o n de scri pti v e i nst r ucti o ns, rec o mm endati o ns, ha r moni zed standard s , set requi rements [3 8 –
4 3 ] , studi es regardi ng si mul at i o ns o r ma teri al studi es ma d e i n l a b o rator y co ndi tions [1 1 – 14,4 4 – 6 7] ,
fi e l d re search [2 ,3 ,5,7 ,51, 68 – 8 0 ] , an d b o o ks o n the to p i c [6 ,9 , 1 0 ] . Ba sed o n these re f ere nces pub l i shed
b et ween 1 9 9 6 an d 2 0 1 5 , a l ist o f i de ntifi ed o n - si te de grada ti o n facto rs was cre a ted . The de grad at i o n
facto rs were di stri b u ted ac co rd i ng to the se v en l ay ers o f the sy stem. T he co n stru cti o n wor ks i n the
su b str at e l ay er m ainl y co ncern the pre par at i o n o f the e x i sti ng exte rn al wa l l . Ad hes i v e, rei nfo rc ement ,
an d fi ni shing l ay er s i ncl ude wor k practi ces wi th mi x ture s a nd mes h appl i catio n. Insu l at i o n an d
mech an i cal an cho rs speci fy the requi rements fo r the i nsu l at i o n pan el s an d mech an i call y f i x ed
an c hor s. The addi ti o na l det ail s general i z e the de fe cts o f the i nst all at i o n s o f au x i lia ry pro ducts , l i ke
wi ndo wsill s an d pl i nth ar eas. T a b l e 1 shows the l i terature u sed fo r the sel ecti o n o f de grada ti o n
facto rs a nd t he l ay er to wh i c h t he facto r i s rel at ed , w her eas e ntir e l i st o f revea l ed o n - si te shortco mi ngs
fo r f urther ev aluati o n i s pre sented i n App endi x A .
Tab le 1 . Mo st rel eva nt deg r a d a tio n fa ct o rs base d o n the li tera tu re r e view .
Laye r Lite rat ure S ource
Sub s trate ( S) [6 ,9 , 1 0 ,56, 64,6 8,73 ]
Ad hesi v e ( D) [6 ,7 , 9 – 12,1 4,15 , 4 6 , 5 6 ,69, 73,76]
Insu l at i o n (I) [6 ,9 , 1 0 ,13, 49,5 0,58 , 7 2 , 7 3 ]
Me cha ni cal a nchors ( A) [6 ,9 , 1 0 ,40, 41]
Rei nfo rce ment (R) [2 ,6 , 9 ,1 0,55 ]
Fi ni shing l ay er (F) [6 ,9 – 1 1 , 1 4 ,69]
Ad di t i o na l d etails ( X) [6 ,9 , 1 0 ,53, 62]
To revea l qu esti o nnai re err o rs , o ne de c l ared an d o ne undecl ared pre - test were co nducted .
Si milar l y , i ndi v i dual pre - te sti ng has b ee n used b y o th er rese archers [8 1 ] an d shown go o d resul ts i n

Figure 3. Demographics of the experts participating in the occurrence and detectabili ty evaluation.
2.3. Selection of Degradation Factors
The list of degradation factors was collected thr ough a literature r eview . The list of shortcomings is
based on descriptive instructions, r ecommendations, harmonized standards, set r equirements [
38
–
43
],
studies r egarding simulations or material studies made in laboratory conditions [
11
–
14
,
44
–
67
], field
r esearch [
2
,
3
,
5
,
7
,
51
,
68
–
80
], and books on the topic [
6
,
9
,
10
]. Based on these r eferences published between
1996 and 2015, a list of identified on-site degradation factors was created. The degradation factors wer e
distributed accor ding to the seven layers of the system. The construction works in the substrate layer
mainly concern the pr eparation of the existing external wall. Adhesive, reinfor cement, and finishing
layers include work practices with mixtur es and mesh application. Insulation and mechanical anchors
specify the r equirements for the insulation panels and mechanically fixed anchors. The additional
details generalize the defects of the installations of auxiliary pr oducts, like windowsills and plinth
ar eas. T able 1 shows the literatur e used for the selection of degradation factors and the layer to which
the factor is related, whereas entir e list of revealed on-site shortcomings for further evaluation is
pr esented in Appendix A .
T able 1. Most relevant degradation factors based on the literatur e review .
Layer Literature Source
Substrate (S) [ 6 , 9 , 10 , 56 , 64 , 68 , 73 ]
Adhesive (D) [ 6 , 7 , 9 – 12 , 14 , 15 , 46 , 56 , 69 , 73 , 76 ]
Insulation (I) [ 6 , 9 , 10 , 13 , 49 , 50 , 58 , 72 , 73 ]
Mechanical anchors (A) [ 6 , 9 , 10 , 40 , 41 ]
Reinforcement (R) [ 2 , 6 , 9 , 10 , 55 ]
Finishing layer (F) [ 6 , 9 – 11 , 14 , 69 ]
Additional details (X) [ 6 , 9 , 10 , 53 , 62 ]
T o r eveal questionnaire err ors, one declared and one undeclar ed pr e-test were conducted.
Similarly , individual pr e-testing has been used by other resear chers [
81
] and shown good r esults
in identifying misinterpr etations [
82
]. The reviews wer e conducted individually and independently ,
and the r esults of the other evaluations were not r evealed. One expert was located in Germany ,

Sustainability 2018 , 10 , 3900 6 of 26
had a doctoral degr ee, and had more than 20 years of experience with the ETICS as a consultant and
supervisor . The second was located in Estonia, had a master ’s degree in civil engineering, and mor e
than 15 years of experience as pr oject manager in ETICS construction. Both experts wer e participating
in the National ETICS Standar ds Committee. During the reviews, 11 irr elevant factors wer e removed
fr om further analysis, and the wording of 16 degradation factors was rephrased to impr ove the
legibility and suitability for systems checked.
2.4. T echnical Risk Priority Number of Degradation Factors
The evaluation system focused on the essential technical performance r equirements set for the
ETICS. W e assumed that if the performance of the system does not meet the desir ed characteristics,
a failur e occurs. T o classify and rate the significance of each failur e, the risk assessment methodology
Failur e Mode Effects Analysis (FMEA) was used as it enables the quantification and prioritization of
risk [ 20 , 21 , 83 ]. The technical risk priority number of a degradation factor was calculated with:
T R P N D F = SV D F × OV D F × DV D F , (1)
wher e TRPN
DF
is the technical risk priority number of a degradation factor , SV
DF
is technical severity
value of a degradation factor , OV
DF
is occurr ence value of a degradation factor , and DV
DF
is the
detectability value of a degradation factor .
The simulation data wer e divided into technical and region-specific components. The framework
of the model is visualized in Figur e 4 , where the occurr ence and detectability are individual
components, and the weighted technical severity value is a combination of eight severity categories.
Su stainab ility 2018 , 10 , x FO R PEE R REV IE W 6 o f 27
Su stainab ility 2018 , 10 , x ; do i: F OR PEER REVIE W www .mdpi .c o m/ jou rna l / su stai n a b i lity
i de ntif y i ng mi si nterpre ta ti o ns [8 2 ] . The revie ws were co nducted i ndi v i dual l y an d i ndepe ndentl y,
an d t he resul ts o f the o ther eval ua ti o ns were not re v e ale d. O ne e x per t w as l o cated i n Germ an y, ha d
a do cto ral de gree , an d ha d mor e tha n 2 0 years o f ex per i ence wi th the ETIC S as a co nsu l ta nt a nd
super v i sor . The seco nd was l o cated i n Esto ni a, ha d a master’s de gree i n ci v i l engi neeri ng , an d mor e
than 1 5 years o f ex per i ence as pro j ect ma n ag er i n ETIC S co nst ructi o n. B o th ex per ts were parti ci pating
i n the N at i o na l ETIC S S ta n dard s C o mm i ttee . Duri ng t he revie ws , 1 1 i rrel ev ant fac to rs were remo v ed
fr o m fur ther a n alysi s, an d the wor di ng o f 1 6 de grada ti o n facto rs w as rep hr ase d to i mpro v e the
l egi b il i ty an d sui tabili ty fo r syste ms checked.
2 . 4 . Tech nical Risk Priority N umbe r of D egrad at ion Fact ors
The eval ua ti o n sys te m fo cused o n the essenti al techni cal per fo rma nce requi remen ts set fo r th e
ETIC S. We assumed t h at i f the per fo rmance o f the sy st em do es not meet the de si red cha r acteri sti cs,
a fai l ure o c curs. To c l as si fy an d ra te the si gnif i can ce o f each fai l ure, the ri sk as sess ment me thod o l o gy
Fa i l ure M o de Effe cts A na l y si s (FM EA ) wa s used as i t e nab l es t he qu anti fi cati o n a nd pr io r i ti z at i o n o f
ri sk [2 0 , 2 1 , 8 3 ] . The tec hn i cal r i sk pri ori ty number o f a degrada ti o n facto r wa s calc ul at ed wi th :

   =  
      ×  
       ×  
       ,

( 1 )
wh ere TRPN DF i s the tech ni cal ri sk pri o r i ty numb er of a de gr ada ti o n fact o r , SV DF i s tech ni cal sev eri ty
value o f a de grad at i o n fac to r , OV DF i s o ccurr ence value o f a de grad at i o n facto r , an d DV DF i s the
de tecta b i l i ty v alue o f a degradatio n facto r .
The si mul at i o n data wer e di v i de d i nto techni cal an d regi o n - speci f i c co m po nents . The
fr am ewo rk o f t he mod el is v i sua l i zed i n Fi gure 4 , wh ere t he o ccurr ence an d de tecta b i l i ty are
i ndi v i dual co mpo nents , and the wei ght ed tech ni cal sev eri ty v alue i s a co m b i na ti o n o f ei ght sev eri ty
categor i es.

Figu re 4 . T he fr a mewo rk o f the tec hn ical relevance mo del . S C = se verity c a tego ry .
The e x per ts e valuate d t he sev eri ty o f the s yste m ’ s pe rf o rma nce, the l i kel i ho o d of o ccurr ence ,
an d de tecta b i l i ty o n a Li ke rt sca l e. L i kert sca l e s fr o m two up to 1 1 poi nts hav e bee n use d i n o ther
rese arch [8 4 ] . Ac co rding to Presto n [8 4 ] , sca l es b el o w o r equa l to fo ur po i nts should b e a v o i de d. For

Figure 4. The framework of the technical relevance model. SC = severity category .
The experts evaluated the severity of the system’s performance, the likelihood of occurrence,
and detectability on a Likert scale. Likert scales from two up to 11 points have been used in other
r esearch [
84
]. According to Pr eston [
84
], scales below or equal to four points should be avoided. For the
severity evaluation, a six-point Likert scale was used to include the value of zero, which simplifies

Sustainability 2018 , 10 , 3900 7 of 26
the interpr etation of the cases where no influence is for eseen. The detectability and occurr ence were
evaluated in a five-point Likert scale. The developed Likert scales are shown the following section.
2.4.1. T echnical Severity
For the building pr oducts used in the European Union, the general international technical
r equirements ar e set by Regulation (EU) Number 305/2011 [
85
] (also Construction Pr oducts Regulation
or CPR), which is the basis for the “Guideline for Eur opean technical approval of External Thermal
Composite System (ETICS) with rendering” (also ET AG 004) [
41
]. The Construction Pr oducts
Regulation pr esumes that buildings and construction products meet the performance r equirements
during their economically r easonable working life and describes seven essential requir ements for
construction pr oducts. “Mechanical resistance and stability” (SC1), “safety in case of fire” (SC2),
“ener gy economy and heat retention” (SC3), and “protection against noise” (SC4) ar e consider ed
in this study as described in the CPR. “Sustainable use of natural resour ces” is explained in ET AG
004 as measur es on the “aspects of durability and serviceability”, which concern durability from
several aspects that ar e differ entiated in this study . The system must pr otect against short-term
weather ef fects like “humidity and weather protection” (SC5), deliver its functions during the whole
service life (“long-term durability”, SC6), and be r esistant to corrosion (“corr osion protection”, SC7).
“Safety in use” considers the resistance to combined str esses caused by normal loads. For clarity in
this r esearch, the label “ability to bypass tensions” (SC8) is used. “Hygiene, health, and environment”
considers the ef fect on the indoor and outdoor environment as well as pollution due to the r elease of
danger ous substances, which is not seen as a separate severity category in this façade construction
technology-r elated study .
Each degradation factor af fects the performance of each severity category , which influences
the total performance of the façade. Aurnhammer [
86
] estimated technical defects concerning the
diminishing value to the users. In the case of a shortcoming in any segment, the final resulting value
decr eases. The degradation severity was evaluated with a weighted impact method, in which all
categories totaled 100%, describing the total failur e in each category . Based on the weighting method
developed by Aurnhammer [
86
], the adjusted distribution (Figur e 5 ) provides an evaluation model to
calculate the weighted technical severity value.
Figure 5. The weight distribution of the severity categories.

Sustainability 2018 , 10 , 3900 8 of 26
The weighted technical severity value for each expert is calculated with Equation (2). The mean
severity value of all experts is the input value for the technical risk priority number calculation in
Equation (1).
SV D F , e = ∑  S R D F , S C , e
S R SC , m a x
× T S C  , (2)
wher e SV
DF ,e
is the weighted severity value of an expert, SR
DF ,SC,e
is the individual rating of an expert
for a severity category , SR
SC,max
is the maximum rating value for the severity category , and T
SC
is the
weight of the severity category accor ding to Figure 5 .
The developed Likert scale for the technical severity rating is shown in T able 2 . The highest rating
was assigned if the failure has a very high ef fect on the r equirement and a scor e of zero was given
when the failur e has no impact on the requir ement. These expert ratings were the input data for the
calculation of weighted technical severity value.
T able 2. Likert scale for the evaluation of technical severity .
Risk Level Characteristic Severity Rating
V ery high T otal failur e of the requir ement 5
High Requirement is highly influenced 4
Moderate
Requirement is moderately influenced
3
Low Requirement is slightly influenced 2
V ery low Requirement is minimally influenced 1
No effect No effect on the r equir ement 0
The validity of the severity values based on expert judgement was tested with the non-parametric
Friedman’s test, which increases the cr edibility of quantification of subjective evaluations [
87
,
88
].
The non-parametric Friedman’s test assesses the dif ference between a number of r elated samples.
The test is used as an alternative for analysis of variances for repeated measur es when the
same parameters have been measur ed on the same subjects, but under dif ferent conditions [
88
].
Friedman’s test was used for each degradation factor separately to detect expert values that ar e in the
critical zone. The 103 degradation factors included 991 individual evaluations; 53 degradation factors
r eceived positive Friedman’s test results with the first analysis, 82 individual evaluations wer e in the
critical zone and a maximum of four r ounds were applied. After the Friedman’s test, the data sets
included four to 12 experimental units. As there wer e enough differ ent components in the calculation,
the inaccuracy of the evaluations did not have a major impact on the final r esults.
2.4.2. Occurrence and Detectability V alue
The pr oba bility o f occurr enc e rates th e incide nt fr equenc y during t he constr ucti on pr ocess.
It is a su bjecti ve evalu ation by th e expert a nd is depe ndent on p ersona l experie nce. The pr e-test
ques tionna ire r eve aled tha t it is impos sible to q uantif y the occur ren ces in a spe cific ra nge and
quan tifica tion of su bjectiv e evalua tion was r equ ire d. The rati ng scale i s shown in T able 3 . The high est
valu e was give n to often -occurr ing fail ure s and the lo west val ue to unli kely fai lur es.
T able 3. Likert scale for the evaluation of occurrence pr obability .
Risk Level Characteristic Occurrence V alue
V ery high Failure is almost certain 5
High Often repeated failur es 4
Moderate Occasional failures 3
Low Relatively few failures 2
V ery low Failure is unlikely 1

Sustainability 2018 , 10 , 3900 9 of 26
The detectability and occurr ence evaluations were classified into five categories. The detectability
value rates the dif ficulty level of on-site detection of the shortcoming. The characteristics are shown in
T able 4 .
T able 4. Likert scale for the evaluation of detectability .
Risk Level Characteristic Detectability V alue
V ery high A potential cause of failure cannot be detected visually .
Additional tests need to be used. High experience requir ed. 5
High In between very high and moderate conditions. 4
Moderate
A potential failur e can be detected visually before completion of
the layer , during the application process or thr ough markings on
the material packages. Mediocre experience r equir ed.
3
Low In between very low and moderate conditions. 2
V ery low Cause of failure can be detected after completion of the layer
with the less experienced observer . 1
The da ta colle ction to d etermin e the dete ctabil ity and oc curr ence va lues was d evelope d using
the De lphi tec hnique, w her e indepe ndent an d anonymo us exper t judgem ents ar e combi ned thr ough
math ematic al aggr egat ion [
35
]. The expec ted outc ome was a co nsensu s between the expe rts. The D elphi
tech nique sh ould be us ed if ther e is no q uantif iable da ta availa ble [
89
]. The tec hnique r equ ire s the
cir cula tion of a qu estion nair e among st the sele cted exp erts. The re is n o specif ic guidel ine to det ermine
when a c onsens us has bee n achieve d. In this s tudy , the cons ensus wa s achieve d when the e xperts
agr eed up on the mea n values o f the gr oup.
Th e ex pe rt s we r e as ke d in di vi dua ll y an d an on ym ou sl y to p r ov id e the ir e va lu at io ns . A cco r di ng t o
th e qu es ti on na ir e, ea ch e xp er t ne ed ed t o pr ovi de e va lu at io ns f or o cc urr en ce a nd d et ec tab il it y . T o ob ta in
a hi gh r es po ns e ra te, a m ee ti ng t im e wi th e ac h exp er t wa s in di vi du al ly o r ga ni zed . D ur ing t he f ac e- to -f ac e
me et in g, t he q ue sti on na ir e wa s co mp let ed b y th e ex pe rt . The r es po ns es f r om a ll e xp er ts we r e su mm ar iz ed
an d me an v al ue s we r e ca lc ul at ed. Th e co lle ct iv e me an r es ult s we r e se nt t o ea ch e xp er t an d th ey w er e
as ke d to r ev is e th eir ev al ua ti on o r ag r ee /di sa gr ee w it h th e co ll ect iv e r es ul t. Du ri ng t he n ex t tw o we ek s,
th r ee p ar ti ci pa nt s ag r ee d wi th th e co ll ec ti ve r esu lt s. T wo e xp er ts r e vi ewe d th e gr ou p r es ul ts af te r
a r em in di ng p ho ne c al l an d st ate d th ei r ag r ee me nt w it h co ns ens us . Ha ll ow ell e t al . [
30
] de sc ri be d th e
“b an dw ag on e ff ec t” , wh er e d eci si on m ak er s ma y fe el p r es su r e to c on fir m th e op in io n of a g r ou p. Du e to
th e fa st a gr ee me nt wi th t he c on se ns us a nd t o in ve st ig ate w he th er t hi s de sc ri be d ef fe ct w as pr es en t,
th e te am o f ex pe rt s wa s br o ug ht p hys ic al ly t og et he r . T he h igh es t an d lo we st e va lu at io ns we r e di sc us se d
wi th t he g r ou p to c he ck i f th er e wer e hi dd en a ss um pt ion s. Po si ti ve ly , the c on se ns us d id n ot c ha ng e af te r
th e me et in g. Th e pri ma ry r ea so n wa s tha t th e in di vi du al e va lu at ion s de pe nd h ig hl y on t he s ki ll s and
ex pe ri en ce o f th e ex pe rt a nd th e r es ul ts m ay v ar y . Th e da ta c ol le cti on p r oc es s wa s co nd uc te d in 2 018 .
3. Results
The objective of this study was to prioritize on-site construction pr ocess activities to enable better
r esource allocation to quality contr ol during construction. The developed technical severity model
combines the ef fect of weighted technical severity , the probability of occurr ence, and the detectability
of the on-site construction work. The output values were divided into layers of the applied system and
ETICS types for analysis. ETICS 1 concerns the purely bonded system with polystyr ene. Polystyrene
with mechanically fixed anchors and supplementary adhesive describe ETICS 2. ETICS 3 repr esents
the mineral wool system with the same fixation type as ETICS 2. The benefit of the differ entiation by
ETICS type is to pr ovide the ability to assign only relevant degradation factors to the simulation under
evaluation. The differ entiation by layers of the system allows the comparison between the sequences
of the construction pr ocess.

Sustainability 2018 , 10 , 3900 10 of 26
3.1. Weighted T echnical Severity V alue
The pr imary va riable fo r TRPN cal culati on is the ave rage wei ghted tec hnical s everity v alue,
whic h consid ers the tec hnical s ignifi cance of th e degrad ation fac tors in th e eight se verity ca tegori es.
The di stribu tion of th e average s everit y values b y layers is s hown in Fi gur e 6 , wher e higher v alues
deno te highe r signif icance. The de gradati on facto rs in the su bstrate a nd adhes ive laye rs have
sign ifican tly diff ere nt sever ity value s when ETI CS types a re co mpar ed. ETI CS 1 is high ly depend ent
on the c haract eristi cs of adhes ion and ha s a higher se verity v alue, whe rea s ETICS 2 and 3 s har e the
fixa tion ris k with mec hanical a nchors a nd have lo wer valu es. In othe r layers , the ET ICS type s have
comp arable v alues.
Su stainab ility 2018 , 10 , x FO R PEE R REV IE W 1 0 o f 2 7
Su stainab ility 2018 , 10 , x ; do i: F OR PEER REVIE W www .mdpi .c o m/ jou rna l / su stai n a b i lity
3 .1 . We igh ted Tech nical Sever ity V alue
The pri ma ry vari a b l e fo r TRPN calc ul at i o n i s the av e rage wei ght ed tech ni cal sev eri ty value ,
wh i ch co nsid er s the tech ni cal si gnif i can ce o f the de grada ti o n facto rs i n the ei ght s ev eri ty cate go ri es.
The di stri b u ti o n o f the av e rage se v eri ty value s by l aye rs i s shown i n Fi gure 6 , wh ere hi gher value s
de note hi gher si gnifi can ce . The de grada ti o n facto rs i n the sub str at e an d adhe si v e l ay ers hav e
si gnif i can tl y d i ff ere nt sev eri ty v alue s whe n ETIC S types are c o mpa red . ETIC S 1 i s hi ghly d epe nd e nt
o n the cha r acteri sti cs o f adh esi o n an d has a hi gher se v eri ty value , wh ere a s ETIC S 2 an d 3 sha re the
fi x at i o n ri sk wi th mech an i cal an c hor s a nd hav e l o wer value s. In o t her l ay ers , t he ETIC S types hav e
co mpa ra b l e v alue s.

Figu re 6 . T he a ve ra ge se verity value by the layer o f the syst em .
The se v eri ty v alue s (S Vs) o f the de gr ada ti o n facto rs were pl aced i n the o rd er o f the co nst ructi o n,
shown i n Fi gure 7 . The co l o red hor i z o nta l l i nes v i sua l i z e the a v era ge value s o f the wei ght ed tech ni c al
rel ev an ce fo r each ETIC S t ype by l ay er . The s tandard de v i at i o ns were the sm alles t i n the su bstra te
(0 .0 4 to 0 . 0 6 ) an d adh esi v e (0 . 0 7 to 0 .08) l ay ers . The c o lo red area s rep rese nt the ran ge o f a speci f i c
l ay er . The gro ups o f de grada ti o n facto rs d i scussed m o re speci f i cal l y are i de nt i f i e d wi th gree n l i nes.
The SV 1 gro up i ncl udes the de grada ti o n facto rs o f th e pure l y b o nded sy stem i n the su bstra te
l ay er, wh i ch i nv o l v es pre parati o n of the surface. S ubstra te co v erage wi th o i l ( S1 b ), dust ( S2 b ),
b i o l o g i cal gro wth (S 3 b ), o ld paint (S 4 b ), as wel l as de cre as ed l o ad b e ari ng c ap acity (S 5 b ) , h a v e hi gh
techni cal sev eri ty.
The seco nd hi ghly rel ev a nt gro up w as SV 2 , wh i ch de s cri b es mi ssing ad hesi v e o n the ed ge s o f
i nsu l at i o n ( D1b ), fr eezi n g of the mi x ture (M 9 b ), ex cee de d wor ki ng ti me o f the adh esi v e (D7 b ), a nd
addi ng uns ui table i ngredi e nts (M 8 ). The hi gh techni cal sev eri ty o f the sub strate a nd adh esi v e l ay ers
i s caus ed b y t he co nst ructi o n activiti es that are respo nsib l e fo r the f i x at i o n o f the sys tem to the ex i sti ng
ex tern al shel l o f the b ui ldi n g. The de grada ti o n facto rs in the su b str at e l ay er i ncl ud e the pre - treatment
o f the surface an d the pro per ti es o f the substrate th at affec t the ch ar acteri sti cs o f adh esi o n. The
ex i sti ng e x teri o r wa l l o f the b ui l di ng mus t resi st t he addi ti o na l l o ad caus ed b y the ETIC S a nd i s
respo nsib l e, to a l arge ex tent, fo r the sta b i l i ty an d adh esi o n cha racteri sti cs o f th e at ta c hed sys te m,
wh et her the fi xatio n rel i es o n mech an i cal a nchors o r adh esi v e. The f actors i n t he su bstra te a nd
adh esi v e l ay ers ha v e a rel ati v el y hi gh i mpa ct o n the m echa ni cal st a b i li ty o f th e sys tem a nd medi o cr e
i nfl uence o n l o ng - term d ura b i l i ty.

Figure 6. The average severity value by the layer of the system.
The severity values (SVs) of the degradation factors wer e placed in the order of the construction,
shown in Figur e 7 . The colored horizontal lines visualize the average values of the weighted technical
r elevance for each ETICS type by layer . The standard deviations wer e the smallest in the substrate
(0.04 to 0.06) and adhesive (0.07 to 0.08) layers. The colored ar eas repr esent the range of a specific layer .
The gr oups of degradation factors discussed more specifically ar e identified with green lines.
The SV 1 gro up inclu des the deg radati on facto rs of the pur ely bonde d system in t he subst rate
laye r , whic h involve s pre parati on of the su rface. Su bstrat e covera ge with oil ( S1b), dus t (S2b),
biol ogical g row th (S3b) , old paint ( S4b), as we ll as decr eas ed load bea ring cap acity (S 5b), have hi gh
tech nical se verity .
The second highly relevant gr oup was SV2, which describes missing adhesive on the edges
of insulation (D1b), freezing of the mixtur e (M9b), exceeded working time of the adhesive (D7b),
and adding unsuitable ingr edients (M8). The high technical severity of the substrate and adhesive
layers is caused by the construction activities that ar e responsible for the fixation of the system to
the existing external shell of the building. The degradation factors in the substrate layer include
the pr e-treatment of the surface and the pr operties of the substrate that affect the characteristics of
adhesion. The existing exterior wall of the building must resist the additional load caused by the
ETICS and is r esponsible, to a large extent, for the stability and adhesion characteristics of the attached
system, whether the fixation relies on mechanical anchors or adhesive. The factors in the substrate and
adhesive layers have a r elatively high impact on the mechanical stability of the system and mediocre
influence on long-term durability .

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Figu re 7 . Sev eri ty va lue o f the deg rada tio n fa ct o r s based o n the steps o f the co ns truc ti o n pro cess .
The hi ghes t tech ni cal i mpa ct wa s ca used by the shortc o mi ngs i n the re i nf o rce ment l ay er, wh i ch
i s respo n si b l e fo r the essenti al ta sk o f stress tr ansmi ss i o n wi thin the sys te m. In a co rre ctl y applie d
l ay er, t he stres ses are tr a ns mi tted to the mes h appl i ed . Th e se facto rs co nsid era b l y i mpa ct mec hani cal
stab i l i ty, b ut also the a b i l i t y to b yp as s te nsio ns, l o ng - term dura b i l i ty , an d weath er pro tectio n. The
r el at i v el y hi gh i mpa ct o f the se sev eri ty cate go ri es can b e ex pl ained b y t he requi reme nt to b ear stre sses
caus ed by t he e x tern al en v i ro n ment , l i ke hy gro therm al ch a nge s duri ng di ff ere nt s easons a nd fr eeze -
thaw cycl es. The two de grada ti o n facto rs wi th hi gh s ev eri ty were i n the SV 3 gro up: a thin l ay er o f
rei nfo rce ment mixtu re (R6) an d the fr eezi ng of the rei nfo rce ment mi x ture (M 9 c) .
Si milar to the adh esi v e l ay e r, mech an i cal a nchors fi x t h e sys te m to t he e x i sti ng e x te rna l s hel l an d
b e ar wi nd sucti o n l o ads. Th ei r techni cal ef fe ct ma i nl y co ncerns t he mec hani cal st a bi li ty o f the sys te m,
wh ere a s all o ther severi ty categor i es remai n ed rat her i rre l ev an t.
T he de grad at i o n facto rs i n t he addi ti o na l de ta i l s l ay er were techni call y as r el evan t . In this st udy ,
t he l ay er i ncl udes mor e ge neral l y de scri b ed shortco m i ngs th at ref l ect the i nst all a ti o n o f addi t i o na l
pro ducts i n co nta ct wi th t he sys te m (i .e. , applic at i o n o f wi ndo wsill s, f i x at i o ns th at r equi re penetrati o n
thro ugh the s yste m, a nd i ns ta l l at i o n o f r o o f ed ge de ta ils). The addi ti o na l de ta i l s hav e hi gh ra ti ngs o n
the se v eri ty categor i es o f e nergy ef fi ci ency, an d, to so me ex te nt , pro t ecti o n ag ainst noi se, weather
pro tecti o n, l o ng - term dura b i l i ty , an d co rro sion pro tecti o n. In co mpa ri son to the i n ternal l ay ers o f the
sys te m, the shortco mi ngs i n this l ay er mostl y affec t the moi sture - i nduced pro b lems a s seala nts fai l
an d en a b l e the e x tern a l mo isture to pe netrate t he sy ste m.
An u ne x pec tedl y hi gh se ver i ty v alue wa s a ssigned t o the fi ni shing co at a nd th e de gradati o n
facto rs i n gro up SV 5 . The ex tern al l ay er , i n addi t i on to i ts aest heti c functi o n , i s respo nsib l e f o r
weather pro tecti o n t o some ex tent, altho ug h the ETIC S i s de si gned to functi o n w i thout the fi ni shing
l ay er. The n at ur al co ndi tions i ncl ude a co m b i na ti o n o f ef fe cts fr o m wh i ch t he e x ter na l l ay er pro v i de s
pro tecti o n : w i nd, rai n, poll utants, rel at i v e hu mi di ty, t emper atur e , an d sol ar radi at i o n. The resul ts
show a hi gher i nfl uence o n the sev eri ty categor i es tha t co nsid er the ex terna l e ff ect s: weat her
pro tecti o n, l o ng - term dura b i l i ty , an d a b i l i ty to b ypas s tensi o ns. The s hor t co mi ngs i n the fi ni s hi ng
l ay er ha d the hi ghest st a n d ard de v i at i o n o f 0 .15. The de grada ti o n facto rs wi th hi gh sev eri ty v alue
i ncl ude the ri sks of the m i x ture : f ree zing of the mi x ture (M 9d) , uns ui table stor ag e co ndi t io ns (M 1 d) ,
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65

0.70

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Average weighted severity value
Degradation facto rs by the sequence of the constru ction p rocess
ETICS 1 ETICS 2 ETICS 3
SV1
SV2
SV3
SV5
SV4
Subs trate Adhesive Insul ation
Anchor
-age
Reinforce-
ment
Finish ing
coat
Additional
details
Average weighted severity value by layers fo r:
ETICS 1 ETICS 2 ETICS 3

Figure 7. Severity value of the degradation factors based on the steps of the construction pr ocess.
The highest technical impact was caused by the shortcomings in the r einforcement layer , which is
r esponsible for the essential task of stress transmission within the system. In a correctly applied layer ,
the str esses are transmitted to the mesh applied. These factors considerably impact mechanical stability ,
but also the ability to bypass tensions, long-term durability , and weather protection. The r elatively
high impact of these severity categories can be explained by the requir ement to bear str esses caused by
the external envir onment, like hygrothermal changes during dif ferent seasons and fr eeze-thaw cycles.
The two degradation factors with high severity wer e in the SV3 group: a thin layer of r einforcement
mixtur e (R6) and the freezing of the r einforcement mixtur e (M9c).
Similar to the adhesive layer , mechanical anchors fix the system to the existing external shell and
bear wind suction loads. Their technical effect mainly concerns the mechanical stability of the system,
wher eas all other severity categories remained rather irr elevant.
The degradation factors in the additional details layer wer e technically as relevant. In this
study , the layer includes more generally described shortcomings that r eflect the installation of
additional pr oducts in contact with the system (i.e., application of windowsills, fixations that requir e
penetration thr ough the system, and installation of roof edge details). The additional details have high
ratings on the severity categories of ener gy efficiency , and, to some extent, protection against noise,
weather pr otection, long-term durability , and corr osion protection. In comparison to the internal layers
of the system, the shortcomings in this layer mostly af fect the moisture-induced pr oblems as sealants
fail and enable the external moistur e to penetrate the system.
An unexpectedly high severity value was assigned to the finishing coat and the degradation
factors in gr oup SV5. The external layer , in addition to its aesthetic function, is r esponsible for
weather pr otection to some extent, although the ETICS is designed to function without the finishing
layer . The natural conditions include a combination of ef fects from which the external layer pr ovides
pr otection: wind, rain, pollutants, relative humidity , temperature, and solar radiation. The r esults
show a higher influence on the severity categories that consider the external ef fects: weather protection,
long-term durability , and ability to bypass tensions. The shortcomings in the finishing layer had the
highest standar d deviation of 0.15. The degradation factors with high severity value include the risks
of the mixtur e: freezing of the mixtur e (M9d), unsuitable storage conditions (M1d), and increased

Sustainability 2018 , 10 , 3900 12 of 26
amount of kneading water (M3d). The lesser risks concern the adhesion with the pr evious layer ,
including missing primer (F1) and a not cur ed reinfor cement layer (F2).
The insulation layer r eceived the lowest average technical severity value. Although the primary
function of the insulation is to r educe thermal conductivity , defects also affect noise pr otection, and all
other shortcomings have extr emely low influence (group SV4). The broken insulation plates (I9) and
airflow on the surface of the substrate (I4) have an incr eased effect on noise pr otection, as well as on
safety in case of fir e. T o some extent, the shortcomings influence the ability of corr osion protection due
to moistur e-induced problems in the system. Otherwise, the shortcomings regar ding the application
of the insulation layer have minimal influence.
3.2. T echnical Severity Ratings
The comparison of unweighted severity ratings of singular severity categories to each other
(Figur e 8 ) showed that the severity categories of mechanical resistance and stability , and long-term
durability wer e affected the most. The standard deviations wer e 1.02 and 0.81, respectively . The upper
quartile of the mechanical resistance and stability category included nine degradation factors,
which emphasizes the r elevance of freezing of mixtur es (M9c, M9b, and M9d) and the substrate
(S10a and S10b), unsuitable mixtur e storage conditions (M1b, M1c, and M1d), unprepar ed substrate
surface (S1b, S2b, and S4b), and usage of unsuitable anchor type (A9). The long-term durability
category induced thr ee factors: freezing of reinfor cement (M9c) and finishing mixtures (M9d) and
a high shar e of kneading water of the finishing layer (M3d).
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an d i ncreased a mount o f knea di ng w at er (M 3 d) . Th e l esser ri sks co ncern the adh esi o n wi th the
pre v i o us l ay er , i ncl ud i ng m i ssing pr i mer (F1 ) an d a not cure d rei nforcement l ay er (F2 ).
The i nsu l at i o n l ay er rec ei v ed the l o west av er ag e tech ni cal sev eri ty value . Al though the pri ma ry
functi o n o f the i nsu l at i o n i s to red uce therma l co nduct i v i ty, de fe cts a l so affec t noise pro tecti o n, an d
all o ther shortco mi ngs have ex tremel y l o w i nf l uence ( gro up SV 4 ) . The b ro ken i nsu l at i o n pl at es (I9)
an d air fl o w o n the surface o f the sub strat e (I4 ) ha v e a n i ncrease d e ff ect o n no i se pro tecti o n , as well
as o n sa fe t y i n cas e o f f i r e . To s o me ex tent , t he sh o rtco mi ngs i nfl uence the a b i l i ty o f c o rr o si o n
pro tecti o n due to mo i sture - i nduced pro b l ems i n the sys tem. Ot herwi se , the shortco mi ngs regardi ng
the appl i catio n o f the i nsu la ti o n l ay er hav e mi ni m al i nfl uence .
3 .2 . T ec h nical Sever ity Rating s
The co mpa ri son o f unw ei ght ed se v eri ty rati ng s o f si ngu l ar sev eri ty ca tego ri es to each o ther
( Fi gure 8 ) show ed tha t the sev eri ty cate go ri es o f mecha ni cal resi sta nce an d st a b i l ity, an d l o ng - term
dura b i l i ty were affec ted th e most . T he st an d ard de v i at i o n s were 1 .0 2 an d 0 .8 1 , respe cti v el y . The
upper qu arti l e o f the mechani cal resi sta nce and st a b i l i t y categor y i ncl uded ni ne d egrada ti o n facto rs ,
wh i ch emph as i z e s the rel ev an ce o f fr eezi ng o f mi x tures (M 9 c, M9 b , an d M9 d) an d t he su b str at e (S 1 0 a
an d S1 0 b ) , unsui table mi x t u re stor ag e co ndi ti o ns (M 1 b , M1 c, an d M1 d) , un pre p are d su b str at e surface
(S 1 b , S2 b , an d S4 b ) , an d usa ge o f uns ui table an cho r type (A 9 ) . The l o ng - term dura b i l i ty categor y
i nduced three facto rs : fr eezi ng o f rei nfo rce ment (M 9 c) a nd fi ni shing mi x tures (M 9 d) an d a hi gh s ha re
o f knea di ng w at er o f the fini shing l ay er (M 3 d) .

Figu re 8 . Av erage un we ig hted tec hn ical se ver ity r a tings by s everity ca tego ry .
The co rre l at io n an alysi s o f the sev eri ty cate go ri es revea l ed hi gh co rrel at i o ns wi th i n the gro ups
o f h i gh - ran ki n g sev eri ty cat ego ri es (S C1 , SC 5, SC6, an d SC 8 ) an d wi thin lo w - ran ki n g categor i es (S C 2 ,
SC 3 , SC4, an d SC 7 ) . The re gressi o n an alysi s o f the low - ranki ng categor i es i ncl u de d ma ny vari a b l es
that rec ei v ed a l o w sco re , a s they hav e no impact , w hi ch en a b l ed the i nterpre t at i o n o f the co rre l at io n
anal ysi s resul t s as i rre l ev a n t. The regr e ssio n a na l ysi s i n the hi gh - ra nking gro up h a d a hi gh l y po si ti v e
R 2 value (0 .6 0 ) for the pair o f lo ng - term dura b i l i ty an d ab i l i ty to b ypa s s tensi o n s ( Fi gure 9 a ) . The
resul ts show ed 6 0 % o f the de gradati o n facto rs th at affec t the ab i l i ty to b yp as s ten si o ns also i ncrease
the value fo r hum i di ty an d weat her pro tecti o n. A s i milar resul t wa s o b ta i ned fr o m the li nea r
regr essi o n anal ysi s fo r the pair o f weat her pro tecti o n and l o ng term - dura b i li ty ( Fi gure 9 b ) , wh i ch ha d
a n R 2 value o f 0 .3 8 . The fai l ure i n the c at ego ry o f we at her pro tecti o n also red uce d the l o ng - term
dura b i l i ty o f the system . Th e o ther three pai rs ( SC 1 and SC 8 , SC1 an d SC 6 , an d S C5 an d SC 8 ) ha d R 2
value s b et ween 0 .2 8 an d 0 .2 9 , pr o v i di ng a mod est ex p l an at i o n o f the mod el. We int erp rete d this as
meani ng th at t he de fe cts t ha t c ause a de cre a se i n me chani cal stab i l i ty also de cr ease the l o ng - term
dura b i l i ty an d the a b i l i ty to bypa ss te nsio ns. W e at her p ro t ectio n de cre as e s t hro ugh the de fe cts i n t he
a b i l i ty to b yp as s te nsio ns.
2.82
0.49
0.44
0.23
1.28
2.95
0.42
1.77
0.00 1.00 2.00 3.00 4.00 5.00
Mechanical resistance and stability (SC1)
Safety in case of fire (SC2)
Energy economy and heat retention (SC3)
Protection against noise (SC4)
Humidity and weather protection (SC5)
Long-term durability (SC6)
Corrosion protection (SC7)
Ability to bypass tensions (SC8)
Unweighted techn ical severity rating
Severity category

Figure 8. A verage unweighted technical severity ratings by severity category .
Th e cor re lat ion a nal ysi s of the s eve rit y cat ego rie s re vea led h igh c orr el ati ons w ith in th e gr oup s of
hi gh- ran king s eve rit y cat ego rie s (SC 1, SC5 , SC6 , and S C8) a nd wi thi n low -ran kin g cat ego rie s (SC 2, SC3 ,
SC 4, an d SC7 ). The r eg r ess ion an aly sis o f the l ow- ran kin g cat egor ies i ncl ude d man y var iabl es th at
r ece ive d a low s cor e, as th ey ha ve no i mpac t, wh ich e nab led t he in terp r eta tio n of the c orr ela tion a nal ysi s
r esu lts a s irr elev ant . Th e r egr es sio n ana lys is in t he hig h-r ank ing g r oup h ad a hi ghly p osi tiv e R
2
va lue
(0 .60 ) for t he pai r of lo ng- ter m dur abi lity a nd ab ili ty to b ypa ss te nsi ons (F igu r e 9 a) . The r es ult s sho wed
60 % of th e degr ada tio n fac tor s tha t affe ct th e abi lit y to by pas s tens ion s als o inc r ease t he va lue f or
hu mid ity a nd wea the r pr ot ecti on. A si mil ar r esu lt wa s obt ain ed fr om t he li nea r re gr es sion a nal ysi s
fo r the p air o f weat her p r ote cti on and l ong t erm -du rab ili ty (F igur e 9 b) , whic h had a n R
2
va lue o f 0.3 8.
Th e fai lur e in t he ca teg ory o f wea the r pr ote cti on al so r edu ced t he lo ng- ter m dura bil ity o f the s yst em.
Th e oth er th re e pai rs (S C1 an d SC8 , SC1 a nd SC6 , and S C5 an d SC8 ) had R
2
va lue s bet ween 0 .28 a nd
0. 29, p ro vid ing a m ode st ex pla nat ion of the m odel . W e int erpr ete d thi s as me anin g tha t the d efe cts t hat
ca use a d ecr ea se in m ech ani cal s tab ilit y als o dec r eas e the lo ng- ter m dur abi lit y and t he abi lit y to by pas s
te nsi ons . W e ath er pr ot ect ion d ecr ea ses t hr ou gh th e def ects i n the a bil ity t o byp ass t ens ion s.

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Figu re 9 . ( a ) L in ear regressio n fo r lo ng - term dura bility ( SC 6 ) a nd a bility to bypass tensio ns ( SC 8 ) , a nd
( b ) humidity and we a the r pro tec tio n ( SC 5 ) a nd lo ng - term dura bility ( SC 6 ) .
3 . 3 . Probab ility V alue
The seco nd rel ev an t co mp o nent to the prio r i ti z at i o n o f the shortco mi ngs i s the pro b a b i l i ty of
o ccurr ence , as i t rates the fr equenc y o f a n i nci de nt duri ng t he co nst ructi o n pro cess . The hi gher value
emph as i z e s t he shortco mi ng s t ha t o ccur mor e o fte n. The a v era ge value s o f the li keli ho o d o f the
o ccurr ence i n the sev e n l aye rs range d fr o m 1 . 4 3 to 2.8 0 out o f 5.0 , as shown i n Fi gure 1 0 .

Figu re 1 0 . Av era ge o cc urr ence va lue by l ayers .
The a v er ag e o ccurr ence v alue s o f the de gr ada ti o n facto rs were pl aced i n t he o rd er o f the
co nst ructi o n pro cess i n Fi gure 1 1 . The av er ag e value s b y l ay er are show n wi th co lo red li nes . The
co mpa ri son b et ween t he th ree ETIC S show ed no si gni fi can t ef fe ct , an d t he di ff er ence i s not shown
separ at el y.
2.20
1.74 1.76 1.82 1.74 1.43
2.80
0.00
1.00
2.00
3.00
4.00
5.00
Av erage occurr ence v alu e
Lay er

Figure 9.
(
a
) Linear regr ession for long-term durability (SC6) and ability to bypass tensions (SC8),
and ( b ) humidity and weather protection (SC5) and long-term durability (SC6).
3.3. Probability V alue
The second r elevant component to the prioritization of the shortcomings is the probability of
occurr ence, as it rates the frequency of an incident during the construction pr ocess. The higher value
emphasizes the shortcomings that occur mor e often. The average values of the likelihood of the
occurr ence in the seven layers ranged from 1.43 to 2.80 out of 5.0, as shown in Figur e 10 .
Su stainab ility 2018 , 10 , x FO R PEE R REV IE W 1 3 o f 2 7
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Figu re 9 . ( a ) L in ear regressio n fo r lo ng - term dura bility ( SC 6 ) a nd a bility to bypass tensio ns ( SC 8 ) , a nd
( b ) humidity and we a the r pro tec tio n ( SC 5 ) a nd lo ng - term dura bility ( SC 6 ) .
3 . 3 . Probab ility V alue
The seco nd rel ev an t co mp o nent to the prio r i ti z at i o n o f the shortco mi ngs i s the pro b a b i l i ty of
o ccurr ence , as i t rates the fr equenc y o f a n i nci de nt duri ng t he co nst ructi o n pro cess . The hi gher value
emph as i z e s t he shortco mi ng s t ha t o ccur mor e o fte n. The a v era ge value s o f the li keli ho o d o f the
o ccurr ence i n the sev e n l aye rs range d fr o m 1 . 4 3 to 2.8 0 out o f 5.0 , as shown i n Fi gure 1 0 .

Figu re 1 0 . Av era ge o cc urr ence va lue by l ayers .
The a v er ag e o ccurr ence v alue s o f the de gr ada ti o n facto rs were pl aced i n t he o rd er o f the
co nst ructi o n pro cess i n Fi gure 1 1 . The av er ag e value s b y l ay er are show n wi th co lo red li nes . The
co mpa ri son b et ween t he th ree ETIC S show ed no si gni fi can t ef fe ct , an d t he di ff er ence i s not shown
separ at el y.
2.20
1.74 1.76 1.82 1.74 1.43
2.80
0.00
1.00
2.00
3.00
4.00
5.00
Average occurr ence value
Layer

Figure 10. A verage occurr ence value by layers.
Th e av er ag e oc cu rr enc e va lu es o f th e de gr ad at ion f ac to rs w er e pl ac ed in t he o r de r of t he c on st ru ct io n
pr oc es s in F ig ur e 1 1 . The a ve ra ge v al ue s by l ay er a r e sh ow n wi th co lo r ed l in es . Th e co mp ar is on b et we en
th e th r ee E TI CS s ho we d no s ig ni fic an t ef fe ct , an d th e di ff er e nce i s no t sh ow n se pa ra te ly .

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Figu re 1 1 . Occ urr ence va lue (OV) o f the deg ra d a tio n fa ct o rs pla ced in o rd er o f the construct io n
pro cess .
The de grad at i o n facto rs i ncl udi ng the addi tional de t ail s rec e i v ed the hi ghest a v er ag e rati ng
(2 .8 0) , f o llowed b y t he su b stra te l ay er (2 .1 2 ) . The shortco mi ngs i n the addi ti o na l de ta il s l ay er are
de scri b ed i n a mor e gener al manner a nd theref o r e incl ude an i ncreased vari ety o f ri sks , wh i ch
pro b a b l y i ncrease the o ccurr ence rate i n co mpa ri son to o ther l ay ers to some ex ten t , wh i ch are mor e
speci fi ca l l y de scri b ed . In the OV1 gro up , the hi g h est o ccurr ence v alue s i ncl uded pro b l ema ti c
structur al ex pa nsio n j o i nts (X1 ) an d penetr at i o ns th ro u gh th e s yste m due to f i x at i o n (X7) .
The su b str at e l ay er i ncl uded activiti es tha t are o f ten i ntentio na l l y not co nducted , an d they do
not caus e a v i si b l e pro b l em unle ss o ther fail ures o c cur (OV2 gro up ) . Suc h deg rad at i o n facto rs
i ncl uded c l ean i ng o f the sur face fr o m b i o l o g i cal gro wth (S 3 a, S3 b ) an d l ev e l l i ng the surface (S 6 a, S7 b ) .
An i ncreased amoun t o f adh esi v e i s suff i c i ent to d ecr e as e the ri sk . A s li ght l y lo we r o ccurr ence v alue
wa s de tecte d fo r the fi ni shi ng l ay er (1 .4 3 ) , p o i nted o ut i n the OV3 gro up .
3 . 4 . Det ectability Va lue
The thir d co mpo nent o f the TRPN c alcul at i o n i s the det e cta b i l i ty of de grada ti o n facto rs duri ng
co nst ructi o n . The a v era ge de tecta b i l i ty v alue r an ge d fr o m 1 . 2 0 to 2 . 82 , as s hown i n Fi gure 1 2 , w here
hi gher val ue s i ndi cate i ncreased r i sk and l o wer d etec ta b i l i ty .
The de grad at i o n facto rs wi th the hi ghe st de tecta b i l i ty value s were i n the adh e si ve l ay er , as this
l ay er i s co v ere d i mm ed i at el y wi th the i nsu l at i o n pl at e, ma ki n g i t i mpo ssible to det ect shortco mi ng s
after appl i catio n wi thout a de structi v e tes t. The seco nd hi ghest r at i ng was fo r the re i nfo rce ment l ay er,
wh ere the mesh i s co v ere d duri ng the appl i catio n. The de tecta b i l i ty remai n ed sli ght l y b et ter , as t he
surface st ays o pen a nd v i si bl e de fe cts can b e de tecte d. T he l ay ers t ha t are accessi b l e fo r qu ali ty co ntrol
fo r a l o nger perio d ha d lo wer de tectab i l i t y v alue s . These l ay ers i ncl uded m echa ni cal an cho rs,
i nsu l at i o n, addi tional d etail s , an d t he fi ni shing l ay er.
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 10 20 30 40 50 60 70 80 90 100
Occurrence value
Degradation facto rs by the sequence of the constru ction p rocess
Substrate
Adhesive
Insulation
Anchorage
Reinforcement
Finishing coat
Additional details
OV2 OV1
OV3
Average oc currence
value of the specific
layer

Figure 11.
Occurrence value (OV) of the degradation factors placed in or der of the construction process.
The degradation factors including the additional details r eceived the highest average rating (2.80),
followed by the substrate layer (2.12). The shortcomings in the additional details layer are described in
a mor e general manner and therefor e include an increased variety of risks, which pr obably increase
the occurr ence rate in comparison to other layers to some extent, which are mor e specifically described.
In the OV1 gr oup, the highest occurrence values included pr oblematic structural expansion joints (X1)
and penetrations thr ough the system due to fixation (X7).
Th e su bs tr at e la ye r in cl ude d ac ti vi ti es t ha t ar e oft en i nt en ti on al ly n ot c ond uc te d, a nd t he y do n ot
ca us e a vi si bl e pr obl em u nl es s ot he r fa il ur e s oc cur ( OV 2 gr ou p) . Su ch d egr ad at io n fa ct or s in cl ude d
cl ea ni ng o f th e su rf ac e fr o m bi olo gi ca l gr ow th ( S3a , S3 b) a nd l ev el li ng t he su rf ac e (S 6a , S7 b) . An i nc r ea se d
am ou nt o f ad he si ve i s su ff ici en t to d ec r ea se t he r is k. A sl ig ht ly l owe r oc cu rr en ce v alu e wa s de te ct ed f or
th e fi ni sh in g la ye r (1 .4 3), p oi nt ed o ut i n th e OV 3 gr o up .
3.4. Detectability V alue
The thir d component of the TRPN calculation is the detectability of degradation factors during
construction. The average detectability value ranged fr om 1.20 to 2.82, as shown in Figur e 12 ,
wher e higher values indicate increased risk and lower detectability .
The degradation factors with the highest detectability values wer e in the adhesive layer , as this
layer is cover ed immediately with the insulation plate, making it impossible to detect shortcomings
after application without a destructive test. The second highest rating was for the r einfor cement
layer , where the mesh is cover ed during the application. The detectability r emained slightly better ,
as the surface stays open and visible defects can be detected. The layers that ar e accessible for quality
contr ol for a longer period had lower detectability values. These layers included mechanical anchors,
insulation, additional details, and the finishing layer .

Sustainability 2018 , 10 , 3900 15 of 26
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Figu re 1 2 . Av era ge de tec tability val ue by l a yer .
The de tect a b i li ty value s o f t he de grad at i o n facto rs are vi sua l i zed i n the o rd er o f the co nst ructi o n
pro cess i n Fi gure 1 3 , wh ere the a v er ag e value s are sho wn wi th co l o red li nes . The s hor tco mi ngs i n the
su b str at e l ay er are v i si b l e f o r qu ali ty co ntrol f o r a lo nger per io d. Ho wev er, the de f ects are o fte n ha rd
to de tect an d requi re addi ti o n al mea s ures to b e t ak e n i n some ca ses ( DV1 gro up ), wh i ch i s the reason
fo r the hi gh st an d ard de vi at i o n (0 . 7 6 ). These de grada ti o n facto rs i ncl uded the l o w lo ad - b eari ng
capa ci ty (S 5 b , S5 a), uns ui table type o f adh esi v e (S 7a , S7 b ), an d chemi cal reacti o n b etwee n the
remai ni ng paint a nd appl i ed adh esi v e (S 4 a, S4 b ). A ddi ti o na l mea sures shoul d b e ta ken to check the
adh esi o n pro per ti es o f th e e x ter na l surface and to test t he pul l - thro ugh strengt h o f th e struct ure. The
vari an ce b et ween the d i ff ere nt ETICS was v ery l o w .
The i nsu l at i o n l ay er ha d a hi gh st a nda rd de v i at i o n (0 .9 2 ) due to the DV2 gro up t ha t h ad a l o w
de tecta b i l i ty v alue , an d t he DV3 gro up th at ha d a hi g h v alue . Hi gh de tect a b i l i ty value s i n the D V3
gro up i ncl uded two shortco mi ngs : co ntinuo us g aps b etween t he i nsu l at i o n l ay er an d su b s trate (I4 )
an d u nfi ni shed di ff usion pr o cess o f the pol ysty rene i ns ul at i o n pl at es (I2 ). On a v era ge, the m ec hani cal
an c hor s h a d go o d de tecta bi li ty (gro up DV5) , ex cep t f o r the three f actors i n gro u p DV4 : cl ean i ng o f
the an c hor hol e (A 10) , applic at i o n o f uns ui ta b l e an cho r type (A 9) , an d i ncreased di am eter o f dr ill ed
an c hor ho l e ( A 1 ) .

Figu re 1 3 . Detec tability value (DV) o f the deg ra da tio n fa ct o rs by the sequence o f the c ons truc tio n
pro cess .
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 10 20 30 40 50 60 70 80 90 100
Dete ctab ility v alu e
Degradat ion facto rs by th e s equ ence of th e constru ction works
Subs trate
Adhesive
Insulati o n
Ancho rage
Reinf o rcement
Finis hi n g co at
Addit io n al details
Ave rage de tectab ili ty
value of the sp ecific
layer
DV5
DV2
DV4
DV3
DV1

Figure 12. A verage detectability value by layer .
The detectability values of the degradation factors ar e visualized in the order of the constr uction
pr ocess in Figure 13 , wher e the average values are shown with color ed lines. The shortcomings in the
substrate layer ar e visible for quality control for a longer period. However , the defects are often har d to
detect and r equire additional measur es to be taken in some cases (DV1 group), which is the r eason for
the high standar d deviation (0.76). These degradation factors included the low load-bearing capacity
(S5b, S5a), unsuitable type of adhesive (S7a, S7b), and chemical r eaction between the remaining paint
and applied adhesive (S4a, S4b). Additional measures should be taken to check the adhesion pr operties
of the external surface and to test the pull-thr ough strength of the structur e. The variance between the
dif ferent ETICS was very low .
The insulation layer had a high standar d deviation (0.92) due to the DV2 group that had a low
detectability value, and the DV3 gr oup that had a high value. High detectability values in the DV3
gr oup included two shortcomings: continuous gaps between the insulation layer and substrate (I4)
and unfinished dif fusion process of the polystyr ene insulation plates (I2). On average, the mechanical
anchors had good detectability (gr oup DV5), except for the three factors in gr oup DV4: cleaning of
the anchor hole (A10), application of unsuitable anchor type (A9), and increased diameter of drilled
anchor hole (A1).
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Figu re 1 2 . Av era ge de tec tability val ue by l a yer .
The de tect a b i li ty value s o f t he de grad at i o n facto rs are vi sua l i zed i n the o rd er o f the co nst ructi o n
pro cess i n Fi gure 1 3 , wh ere the a v er ag e value s are sho wn wi th co l o red li nes . The s hor tco mi ngs i n the
su b str at e l ay er are v i si b l e f o r qu ali ty co ntrol f o r a lo nger per io d. Ho wev er, the de f ects are o fte n ha rd
to de tect an d requi re addi ti o n al mea s ures to b e t ak e n i n some ca ses ( DV1 gro up ), wh i ch i s the reason
fo r the hi gh st an d ard de vi at i o n (0 . 7 6 ). These de grada ti o n facto rs i ncl uded the l o w lo ad - b eari ng
capa ci ty (S 5 b , S5 a), uns ui table type o f adh esi v e (S 7a , S7 b ), an d chemi cal reacti o n b etwee n the
remai ni ng paint a nd appl i ed adh esi v e (S 4 a, S4 b ). A ddi ti o na l mea sures shoul d b e ta ken to check the
adh esi o n pro per ti es o f th e e x ter na l surface and to test t he pul l - thro ugh strengt h o f th e struct ure. The
vari an ce b et ween the d i ff ere nt ETICS was v ery l o w .
The i nsu l at i o n l ay er ha d a hi gh st a nda rd de v i at i o n (0 .9 2 ) due to the DV2 gro up t ha t h ad a l o w
de tecta b i l i ty v alue , an d t he DV3 gro up th at ha d a hi g h v alue . Hi gh de tect a b i l i ty value s i n the D V3
gro up i ncl uded two shortco mi ngs : co ntinuo us g aps b etween t he i nsu l at i o n l ay er an d su b s trate (I4 )
an d u nfi ni shed di ff usion pr o cess o f the pol ysty rene i ns ul at i o n pl at es (I2 ). On a v era ge, the m ec hani cal
an c hor s h a d go o d de tecta bi li ty (gro up DV5) , ex cep t f o r the three f actors i n gro u p DV4 : cl ean i ng o f
the an c hor hol e (A 10) , applic at i o n o f uns ui ta b l e an cho r type (A 9) , an d i ncreased di am eter o f dr ill ed
an c hor ho l e ( A 1 ) .

Figu re 1 3 . Detec tability value (DV) o f the deg ra da tio n fa ct o rs by the sequence o f the c ons truc tio n
pro cess .
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 10 20 30 40 50 60 70 80 90 100
Detectability value
Degradation facto rs by the sequence of the constru ction works
Substrate
Adhesive
Insulation
Anchorage
Reinforcement
Finishing coat
Additional details
Average detectab ility
value of the specific
layer
DV5
DV2
DV4
DV3
DV1

Figure 13.
Detectability value (DV) of the degradation factors by the sequence of the
construction pr ocess.

Sustainability 2018 , 10 , 3900 16 of 26
3.5. T echnical Relevance According to the Risk Priority Number
The technical risk priority number (TRPN) is a combination of the weighted technical severity
value, the detectability value, and the occurrence value. The r esults by layer and ETICS type are shown
in Figur e 14 , whereas Figur e 15 positions the degradation factors according to the TRPN in the or der
of the construction pr ocess.
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3 . 5 . Tech nical R ele v ance A cco rding to t h e Ris k P riori ty N u mber
The tech ni cal ri sk prio ri ty numb er (T RP N) i s a co m b i na ti o n o f the wei ght ed tec hn i cal se v eri ty
value , the de tect a b i l i ty v al ue , an d the o ccurr ence value . The res ul ts b y l a yer a n d ETIC S type are
shown i n Fi gure 1 4 , wh ere as Fi gure 1 5 po si tions the de gradati o n facto rs accor ding to the T RP N i n
the o rd er o f the c o nst ructi o n pro cess.

Figu re 1 4 . Av era ge value o f tec hn ical ri sk p ri o ri ty number by la y er an d ETICS type .
The co rre l at io n an d regr essi o n an alysi s b etwee n the pai rs o f sev eri ty v alue an d o ccurr ence value ,
an d se v eri ty v alue a nd de tecta b i l i ty v alue , show ed no rel ev an t co rre l at i o n. Be tween the v ari a b l es o f
o ccurr ence v alue an d de tec tabil i ty v alue , there i s a we ak neg at i v e co rre l at io n ( r = – 0 .2 4), though the
R 2 i n the li nea r regr essi o n wa s 0 .0 5 9 , wh i ch do es not ex pl ain the rel at i o nsh i p b et ween the v ari a b l es.
In co mpa ri son to the a v e rage wei ght ed se v eri ty va l ue s shown i n Fi gure 7 , t he rei nfo rce ment,
su b str at e , a nd adh esi v e l aye rs retai ned thei r hi gh a v er ag e rel evance r at i n g. T he de v i at i o n i n all l ay ers
wa s rel at i v el y hi gh. In the s ubstra te an d ad hesi v e l ay er s , ETIC S 1 i ncreased TRPN value s due to the
di ff er ence s i n sev eri ty value s b etwee n the syste ms. Occurre nce an d de tect a b i l ity v alue s ha d no
si gnif i can t di fference i n com p ari son to the ETIC S type s o b ser v ed .
The hi ghly rel ev a nt de gr a dati o n facto rs i n the su b s tr at e l ay er are show n i n the techni cal ri sk
( TR ) 1 gro up ( Fi gure 1 5 ) . The i nci de nce wh en the s ubstra te i s co v ere d wi th chemi call y reacti ng
remai ni ng p aint (S 4 b ), us age o f uns ui table adh esi v e ty pe (S 7 b ) , a nd l o w hu mi di ty o f th e su bstr at e as
i nor ga ni c adh esi o n i s appli ed (S 8 b ) are hi ghly re l ev ant fo r ETIC S 1 . The sys tems wi th mechani cal
an c hor s a nd sup pl ement ar y ad hesi v e (E TICS 2 an d ET ICS 3 ) were hi ghl y i nfl uenced b y the l o w l o ad -
b e ari ng cap acity o f the su bstrate (S 5 a). In t he l o w rel e van ce gro up TR 2 (su b s trat e co v ere d wi th o i l ;
S1 a, S1 b ) , the re l ev an ce de c reased due to v ery l o w value s o f o ccurr ence an d de tecta b i l i ty .
The ad hesi v e l a yer h a d the most rel ev a nt shortco m i ng s i n the T R3 gro up . Ins uf fi c i ent adh esi v e
(S 3 a, S3 b ) rec ei v ed v ery hi gh o ccurr ence an d de tect a b i l i ty v alue s, i ncrea s i ng i ts rel ev an ce. T hree
de gradati o n facto rs wi th rel at i v el y hi gh de tecta b i l i ty value s also b el o ng to this gro up: d ry curi ng
co ndi tions (M 1 1 b ) , l ack o f pre ssure duri ng appl i cation o f i nsu l at i o n pl at es ( D8 b ) , an d adh e si v e not
rubb ed i nto mi neral woo l ins ul at i o n pl at e ( D4a ). The l o w rel ev an ce gro up TR4 i n cl uded the mi x ture -
rel at ed facto rs tha t red uced thei r rel ev an ce due to thei r lo w o ccurr ence v alue . The facto rs i ncl ud e
o nl y the mi xture pre p ara ti o n pro cess: wro n g m at eri al s to rage co ndi ti o ns (M 1 a, M2b ), cl o ts remai n i n
the mi x t ure duri ng mixing pro cess (M 2 a, M2 b ) , an d hi gh s ha r e o f knea di ng water ( M3 a).
The i nsu l at i o n l ay er an d mec hani cal a n cho r s i ncl uded the m ajo ri ty o f the d egradatio n facto rs i n
the l o w re l ev an ce gro up T R 6 . Al though the o ccurr ence v alue o f the shortco mi ngs fo r mecha ni cal
an c hor s was rel at i v el y hi gh ( Fi gure 1 1 ) , the go o d de tec tabil i ty an d b el o w a v era ge techni cal sev eri ty
red uced the TRPN rel ev ance . Ho wev er , there were three de grada ti o n facto rs wi t h a hi gh TRPN i n
the T R5 gro up . Al though c o nti n uo us gaps t hat en a b l e an i nter na l air fl o w (S 4 ) ha d hi gh rel evance i n
all three co mpo nents , i ncreased di am eter o f dr il l ed an c hor hol e ( A1 ) an d uns ui tabl e an cho r type (A 9 )
ha d i ncreased rel evance du e to dif f i cul t d etec tabili ty. The d etec ti o n i s mor e pro b l e ma ti c i n this l ay er
as t he qu ali ty check mus t o ccur duri ng th e appl i cati o n pro cess.
Substrate Adhesive Insulation Anchorage Reinforce-
ment
Finishing
coat
Additional
details
ETICS 1 2.09 1.90 0.90 1.77 1.00 1.49
ETICS 2 1.61 1.50 0.90 1.00 1.77 1.00 1.49
ETICS 3 1.62 1.55 0.93 1.00 1.73 1.00 1.49
0.00
0.50
1.00
1.50
2.00
2.50
Technical risk prio rity
number
Layer

Figure 14. A verage value of technical risk priority number by layer and ETICS type.
The corr elation and regr ession analysis between the pairs of severity value and occurrence value,
and severity value and detectability value, showed no r elevant correlation. Between the variables of
occurr ence value and detectability value, there is a weak negative corr elation ( r = –0.24), though the
R
2
in the linear r egression was 0.059, which does not explain the r elationship between the variables.
In comparison to the average weighted severity values shown in Figur e 7 , the reinfor cement, substrate,
and adhesive layers r etained their high average relevance rating. The deviation in all layers was
r elatively high. In the substrate and adhesive layers, ETICS 1 increased TRPN values due to the
dif ferences in severity values between the systems. Occurrence and detectability values had no
significant dif ference in comparison to the ETICS types observed.
The highly r elevant degradation factors in the substrate layer are shown in the technical risk (TR)1
gr oup (Figure 15 ). The incidence when the substrate is covered with chemically r eacting remaining
paint (S4b), usage of unsuitable adhesive type (S7b), and low humidity of the substrate as inor ganic
adhesion is applied (S8b) ar e highly relevant for ETICS 1. The systems with mechanical anchors
and supplementary adhesive (ETICS 2 and ETICS 3) wer e highly influenced by the low load-bearing
capacity of the substrate (S5a). In the low relevance gr oup TR2 (substrate covered with oil; S1a, S1b),
the r elevance decreased due to very low values of occurr ence and detectability .
T he a d he si v e la y er h a d th e mo s t r e le va n t sh o rt c om in g s in t h e TR 3 g r ou p . I ns u ff ic i en t a dh e si ve ( S 3a ,
S 3b ) r e ce i ve d v er y hi g h oc c ur r e nc e a nd d e te ct a bi l it y v al ue s , in c r ea s in g i ts r el e va nc e . Th r ee d eg r ad a ti on
f ac t or s wi t h r e la ti v el y h ig h d et ec t ab i li t y va lu e s al s o be l on g to t hi s g r ou p : dr y c ur in g c on d it i on s (M 1 1b ) ,
l ac k o f pr es s ur e du r in g ap p li c at io n o f in s ul a ti on p l at e s (D 8b ) , an d a dh e si ve n o t r ub b ed i nt o m in e ra l wo o l
i ns u la ti o n pl a te ( D4 a ). T he l ow r e le va n ce g r ou p TR 4 i nc l ud ed t h e mi x tu r e -r el a te d f ac to r s th a t r ed u ce d
t he i r r el e va n ce d ue t o t he i r lo w o cc ur r en ce v a lu e . T he f a ct or s i nc l ud e o nl y t he m ix t ur e pr e pa ra t io n p r oc e ss :
w r on g m at e ri a l st or a ge c o nd i ti on s ( M1 a , M2 b) , c lo t s r em a in i n t he m i xt ur e d ur in g m ix i ng p r o ce s s (M 2 a,
M 2b ) , an d hi g h sh a r e of k n ea d in g w at er ( M 3a ) .
The insulation layer and mechanical anchors included the majority of the degradation factors
in the low r elevance group TR6. Although the occurr ence value of the shortcomings for mechanical
anchors was r elatively high (Figure 11 ), the good detectability and below average technical severity
r educed the TRPN relevance. However , there wer e three degradation factors with a high TRPN in the
TR5 gr oup. Although continuous gaps that enable an internal airflow (S4) had high r elevance in all
thr ee components, increased diameter of drilled anchor hole (A1) and unsuitable anchor type (A9) had

Sustainability 2018 , 10 , 3900 17 of 26
incr eased relevance due to dif ficult detectability . The detection is mor e problematic in this layer as the
quality check must occur during the application pr ocess.
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Figu re 1 5 . Techn ica l r is k (TR) priority n umb er o f the deg ra d a tio n fa ct o rs in o rd er o f the c ons truc tio n
pro cess .
The rei nfo rce ment l ay er h a d the hi ghest a v er ag e T R PN a nd the m ajo ri ty o f th e de gradati o n
facto rs were po si t i o ned nea r the av er ag e value ( the TR7 gro up ). The de grada ti o n facto rs o f the t hi n
rei nfo rce ment l ay er (R6) an d l ay ers not applie d i n wet to wet c o ndi t i o n (R7) i n the TR8 gro up red uce d
the a b i l i ty to b yp ass ten si o ns i nto the me sh an d were t h e most rel evant . T hi n rei nfo rce ment l ay er ( R6)
ha d, i n co mp ari son , a hi ghe r sev eri ty value due to t he i mpa c t o n t he l o ng - term dur a b i l i ty b ut i s e as i er
to d etec t as the pa ttern o f t he me sh i s v i si b l e afte r c o m pl etio n o f the l ay er. L a yers not appl i ed i n wet
to wet c o ndi tion ( R7) can be d etec ted o nl y during the appl i catio n pro cess.
The ri sks i n t he fi ni sh i ng l a yer, mostl y a ssem b l ed i n th e TR9 gro up , decre a sed its rel ev an ce d ue
to the l o w o ccurr ence value . The l ay er h as no de gr ada ti o n facto rs th at are co nsid ere d hi ghly rel ev a nt
to the syste m’s pe rf o rmanc e.
The shortco mi ngs i n the addi ti o na l de ta i l s l ay er de cre as ed the rel ev an ce due to thei r lo w
de tecta b i l i ty v alue b ut re m ained rel at i v el y hi gh as the fai l ure s o ccur rath er o fte n. Mo st pro b l ema ti c
wa s moi sture penetra ti o n int o the sys tem due to prob l em at i c so l uti o n wi ndo wsill s (X2 ) an d o ther
fi x ed f ram e c o nn ect i o ns (X 4 ) i n the TR10 gro up .
4 . Dis cus si on
Thi s secti o n revie ws th e res earch me thod fr o m two as p ects an d di scus ses future a ppl i cati o ns .
The FME A method was i ni ti al l y de v el o ped i n the 1 9 50s as a mi l i ta ry pro ced ure i n the US A, an d
si nce then, cri ti cs hav e po int ed o ut the fl a ws. T he FM EA method h as b ee n used i n the co n structi o n
i ndustry i n se v eral studi es [2 0 ,21, 83] . Layz el l [ 8 3 ] applie d the method to a si mi l ar cl addi ng sys tem
an d st at ed that the appl i catio n an d the resul ts o f the method de pend o n the ava i l ab i l i ty o f the data .
The dat a i n this rese arch i n v o l v ed quantif yi ng t he s ub j ecti v e e valuati o ns o f th e ex per ts. If mor e
quantif i ab l e o b ser vatio ns a re ma de fo r an y o f the co m po nents (se v eri ty, o ccurr ence , o r de tectab i l i ty),
the dat a co ul d b e mor e speci fi c . Ho wev er, co mpar at i v e rel evance i s not ex pec ted to di ff er
si gnif i can tl y . At this mome nt , there are no mor e specific qu an ti fi ed data a vail ab l e. Nev erthel ess, the
o utco me s o f the si ngle par a meters as wel l as the T RPN resul ts were l o gi cal. Ad d i tion al de gradati o n

Figure 15.
T e ch n ic a l r is k ( TR ) p r io r it y n u mb e r of t h e d eg r ad a t io n f ac t o rs i n o r d er o f t h e co n st r u ct i o n pr oc es s .
The r einforcement layer had the highest average TRPN and the majority of the degradation
factors wer e positioned near the average value (the TR7 group). The degradation factors of the thin
r einforcement layer (R6) and layers not applied in wet to wet condition (R7) in the TR8 gr oup reduced
the ability to bypass tensions into the mesh and wer e the most relevant. Thin reinfor cement layer (R6)
had, in comparison, a higher severity value due to the impact on the long-term durability but is easier
to detect as the pattern of the mesh is visible after completion of the layer . Layers not applied in wet to
wet condition (R7) can be detected only during the application pr ocess.
The risks in the finishing layer , mostly assembled in the TR9 group, decr eased its r elevance due to
the low occurr ence value. The layer has no degradation factors that are consider ed highly r elevant to
the system’s performance.
The shortcomings in the additional details layer decreased the r elevance due to their low
detectability value but r emained relatively high as the failur es occur rather often. Most problematic
was moistur e penetration into the system due to problematic solution windowsills (X2) and other fixed
frame connections (X4) in the TR10 gr oup.
4. Discussion
This section r eviews the resear ch method from two aspects and discusses futur e applications.
The FM EA metho d was initi ally dev eloped i n the 1950s a s a milita ry pr ocedur e in th e USA,
and si nce then , critics h ave poin ted out the f laws. The FM EA method h as been us ed in the con struc tion
indu stry in se veral stu dies [
20
,
21
,
83
]. Layz ell [
83
] appl ied the me thod to a sim ilar cla dding sys tem and
stat ed that th e applic ation and t he r esults of t he metho d depend o n the avai labilit y of the dat a. The data
in thi s res ear ch invol ved quan tifying t he subje ctive ev aluati ons of the ex perts. If mor e quan tifiab le
obse rvatio ns ar e made for a ny of the com ponent s (severi ty , occu rr ence, or de tectab ility), t he data co uld
be mor e spe cific. Howev er , compara tive r eleva nce is not e xpecte d to differ s ignifi cantly . At thi s moment ,

Sustainability 2018 , 10 , 3900 18 of 26
ther e ar e no mo re sp ecific qu antifi ed data av ailable . Nevert heless , the ou tcomes o f the singl e parame ters
as wel l as the TRP N res ults wer e log ical. Additio nal degr adation f actors s hould be i ntegra ted into th e
mode l and eval uated as t echnica l aspect s of ETICS o r its appl icatio n pro cess alt er .
Secondly , the results of the model ar e a pr oduct of three variables: severity , occurrence,
and detectability . Puente [
22
], Bowles [
23
], and W ang [
24
] ar gued that simple multiplication of ordinal
scales might be misleading, as dif ferent combinations might pr oduce the same output value. There ar e
also concerns about the interpr etation of the results of this r esearch. The outcomes of detectability and
occurr ence are the r esult of subjective expert judgement. The change in one variable has a r elatively
lar ge impact on the risk, upon which the final recommendations wer e based. In the earlier work of
Bowles [
90
], a disadvantage was detected in the occasion when multiple severity effects ar e occurring.
T o r educe the impact of this disadvantage, a weight factor of the technical severity categories was
implemented, and the analysis aimed to observe the impact on the system’s total performance.
The external envelope of a building is also exposed to weather ef fects after the completion of the
application pr ocess. The materials are af fected by radiation [
79
], pollution [
3
], fr eeze-thaw cycles [
44
],
humidity , the dir ection of the façade, and changes in porosity [
45
,
67
], which all impact the durability
of the façade. Finnish resear ch on the hygrothermal behavior of ETICS [
60
] highlighted that the high
r elative humidity during freeze-thaw cycles is pr oblematic, and there is a need for incr eased protection
against fr ost attack in cold climates. Therefor e, we expect that in milder climate conditions, on-site
shortcomings will appear in the long term. In this study , the climate condition considerations may have
af fected the probability of occurr ence of the degradation factor . T o mitigate this influence, the experts
evaluated the occurr ence frequency of the shortcomings observed during the construction pr ocess and
this was not confused with the occurr ence of visible degradation during the exploitation period.
Additionally , the latency of the shortcoming has an economic effect, as repair costs incr ease
the size of investment and af fect the decisions on quality control. The cost component is highly
r elevant in terms of the owner ’s and contractor ’s quality considerations. Equilibrium could be found
in futur e resear ch between quality increase and risk mitigation. T o find the cost component of ETICS,
several aspects should be consider ed. The economic component is project-specific and depends on the
chosen system, logistics, general economic situation in the r egion, latency period of the shortcoming,
and other aspects.
In this study , the model included thr ee components in the mathematical aggregation. T o consider
the impact of climate and the cost of r epair , a multiplier could be developed to calibrate the r elevance.
Futur e resear ch could implement these considerations into a unified model.
5. Conclusions and Recommendations
The usage of External Thermal Insulation Composite Systems (ETICSs) is incr easing in Europe
as the existing dwellings ar e refurbished accor ding to newly introduced ener gy efficiency measur es.
The façade system has advantages for the building and owners but requir es additional quality contr ol to
r educe the degradation caused by often-occurring minor shortcomings during the construction process.
W e developed a technical severity evaluation model to quantify the r elevance of on-site
shortcomings of ETICS. The model followed the Failur e Mode Effects Analysis method and consider ed
the technical severity , and the pr obability of occurrence and detectability of deviations. The data were
collected fr om experts’ judgement and validated with the non-parametric Friedman’s test and the
Delphi technique. The impact of the selected 103 degradation factors were quantified and pr esented
in the or der of the construction process. The technical r elevance assessment model considered the
technical severity , occurr ence probability , and detectability of the degradation factors.
The technical severity evaluation r evealed that the ETICS construction process significantly
alters the r esilience of the system in regar d to mechanical stability , long-term durability , ability to
bypass tension, and weather pr otection. The preparation of substrate and application of adhesive ar e
important factors, as are the activities that involve the r einforcement and finishing layer . The occurrence
pr obability component reduced the r elevance of the finishing layer , but added value to additionally

Sustainability 2018 , 10 , 3900 19 of 26
added details (i.e., windowsills, plinth details). The detectability component was more r elevant for
the application of mixtur es in the adhesive and reinfor cement layers. The final output of the study ,
technical risk priority number (TRPN), emphasized that the most r elevant aspect is the reinfor cement
layer for all ETICS types, and the significance of adhesion for the pur ely bonded system.
Based on the r esults of the study; the following general aspects should be considered during
r esource allocation for quality contr ol:
1.
The adhesion to the exterior façade of the building is highly r elevant for the purely bonded
ETICS. During the application pr ocess, the degradation factors which influence the adhesion
characteristics have a very high impact on the technical severity of the system. These shortcomings
ar e hard to detect as they ar e covered for further inspection shortly .
2.
The pr eparation process of the r einforcement mixtur e and the application of the mesh have a high
technical risk as shortcomings occur often. The layer is r esponsible for distributing internal
and external str ess. If a failure occurs, the anomalies evolve and enable moistur e to penetrate
the system.
3.
The failur es during the application of additional details (windowsills, fixed frames, plinth areas,
and other fixings) often occur and have sever e technical consequences but are detectable.
4.
The failur es that occur during construction in the insulation, anchorage, and finishing layers have
r educed risk, as they occur rather rarely and ar e visually detectable. Nevertheless, the technical
severity r emains high for mechanical anchors.
The outcomes of the technical r elevance model enable the allocation of resour ces on more
r elevant degradation factors, which occur often and are har d to detect, to avoid the loss of technical
performance. In case of r elevant changes to the requir ements, construction technology , or construction
materials, the developed model can be r eapplied after the components are quantified accor ding to the
developed method.
Author Contributions:
V .S. designed the study , collected and analyzed the data and wrote the paper .
F .V . supervised and reviewed the paper .
Funding:
This work was supported by institutional resear ch funding of the Estonian Ministry of Education and
Research IUT1 − 15 “Nearly-zer o energy solutions and their implementation on deep r enovation of buildings”.
Acknowledgments:
W e would like to expr ess our gratitude to the experts in Germany and Estonia who shared
their experience and knowledge during this resear ch.
Conflicts of Interest:
The authors declare no conflict of inter est. The funders had no r ole in the design of the
study; in the collection, analyses, or interpr etation of data; in the writing of the manuscript, and in the decision to
publish the results.

Sustainability 2018 , 10 , 3900 20 of 26
Appendix A
T able A1. Data for Equation (1).
Sequence ID Layer Description ETICS 1 ETICS 2 ETICS 3 SC1 SC2 SC3 SC4 SC5 SC6 SC7 SC8 SV OV DV TRPN
1 S1a S Substrate is covered with gr ease or oil x x 2.7 0.4 0.0 0.2 0.4 2.7 0.4 1.5 0.33 1.0 1.2 0.39
2 S1b S Substrate is covered with gr ease or oil x 4.3 0.3 0.0 0.2 0.3 3.3 0.3 1.8 0.46 1.0 1.4 0.64
3 S2a S Substrate is covered with dust or dirt x x 2.6 0.4 0.0 0.2 0.4 2.6 0.4 1.6 0.32 2.4 1.4 1.08
4 S2b S Substrate is covered with dust or dirt x 4.2 0.3 0.0 0.2 0.3 3.3 0.3 1.9 0.45 2.4 1.6 1.72
5 S3a S Substrate is covered with biological growth x x 2.6 0.4 0.0 0.2 0.4 2.6 0.4 1.5 0.32 2.8 1.6 1.43
6 S3b S Substrate is covered with biological growth x 3.9 0.4 0.0 0.2 0.4 3.5 0.4 2.1 0.45 3.0 1.6 2.14
7 S4a S
Substrate is covered with paint or other material which can chemically r eact with adhesive
x x 2.8 0.6 0.3 0.2 0.5 2.8 0.5 1.7 0.36 2.4 2.8 2.39
8 S4b S
Substrate is covered with paint or other material which can chemically r eact with adhesive
x 4.0 0.3 0.3 0.0 0.4 3.6 0.1 2.2 0.45 2.6 3.0 3.53
9 S5a S Substrate is under required load-bearing capacity x x 3.7 0.4 0.0 0.2 0.4 3.4 0.6 1.8 0.42 2.2 3.2 2.99
10 S5b S Substrate is under required load-bearing capacity x 4.0 0.4 0.0 0.2 0.4 3.6 0.6 2.1 0.46 1.6 3.4 2.49
11 S6a S Substrate has large unevenness or has detached areas x x 2.1 0.3 0.6 0.3 0.4 2.0 0.6 1.2 0.26 3.6 1.8 1.69
12 S6b S Substrate has large unevenness or has detached ar eas x 2.9 0.3 0.6 0.3 0.4 2.4 0.6 1.3 0.33 3.0 1.6 1.60
13 S7a S Unsuitable surface (too smooth) which reduces adhesion properties x x 2.3 0.7 0.0 0.3 0.7 2.2 0.7 1.0 0.29 2.0 3.3 1.94
14 S7b S Unsuitable surface (too smooth) which reduces adhesion pr operties x 3.7 0.0 0.4 0.0 0.0 2.4 0.7 1.4 0.37 2.0 3.7 2.73
15 S8a S Substrate has very low humidity (inorganic adhesive) x x 2.5 0.4 0.0 0.2 0.5 2.5 0.8 1.6 0.31 2.3 2.5 1.73
16 S8b S Substrate has very low humidity (inorganic adhesive) x 4.0 0.4 0.0 0.2 0.7 3.2 0.8 1.9 0.45 2.5 2.5 2.78
17 S9a S Substrate is very wet (raining in prior to application of adhesive) x x 2.4 0.5 0.3 0.2 0.7 2.4 0.7 1.3 0.31 2.2 1.8 1.21
18 S9b S Substrate is very wet (raining in prior to application of adhesive) x 3.6 0.5 0.3 0.2 0.7 3.0 0.7 1.5 0.41 2.2 2.0 1.81
T able A2. Data for Equation (2).
Sequence ID Layer Description ETICS 1 ETICS 2 ETICS 3 SC1 SC2 SC3 SC4 SC5 SC6 SC7 SC8 SV OV DV TRPN
19
S10a
S Substrate is frozen during the application (inor ganic adhesive) x x 4.0 0.2 0.4 0.0 0.0 3.8 0.0 2.2 0.45 1.4 2.2 1.39
20
S10b
S Substrate is frozen during the application (inor ganic adhesive) x 4.2 0.2 0.4 0.0 0.0 4.2 0.0 2.2 0.48 1.4 2.2 1.47
21
M1a
D Unsuitable mixture storage conditions x x 2.8 0.0 0.0 0.0 0.0 2.6 0.0 1.5 0.30 0.8 3.0 0.72
22
M1b
D Unsuitable mixture storage conditions x 4.0 0.0 0.0 0.0 0.0 3.6 0.0 1.8 0.42 0.8 3.0 1.02
23
M2a
D The mixing pr ocedures do not remove clots x x 2.1 0.0 0.0 0.0 0.0 1.6 0.0 0.4 0.21 1.4 2.6 0.75
24
M2b
D The mixing pr ocedures do not remove clots x 2.6 0.0 0.0 0.0 0.0 2.0 0.0 0.8 0.26 1.2 2.6 0.81
25
M3a
D High share of kneading water x x 2.4 0.3 0.0 0.2 0.7 2.2 0.4 1.0 0.28 1.4 3.0 1.19
26
M3b
D High share of kneading water x 3.2 0.3 0.0 0.2 0.8 2.4 0.4 1.2 0.35 1.8 3.0 1.90
27
M4a
D Low share of kneading water x x 2.6 0.4 0.0 0.3 1.0 2.4 0.5 1.1 0.31 1.5 3.0 1.40
28
M4b
D Low share of kneading water x 3.1 0.0 0.0 0.0 0.7 2.3 0.0 1.6 0.33 1.5 3.0 1.47
29 D1a D Missing adhesive on the edges of insulation (polystyrene) x 2.3 1.6 2.2 1.1 1.6 3.0 0.6 1.7 0.40 1.5 3.3 1.97
30 D1b D Missing adhesive on the edges of insulation (polystyrene) x 3.3 1.5 2.0 1.0 1.7 3.4 0.5 1.5 0.47 1.5 3.3 2.30
31 D2a D Missing adhesive in the center of insulation (polystyrene) x 2.4 0.4 0.3 0.3 1.2 2.7 0.7 1.1 0.32 1.3 2.8 1.09
32 D2b D Missing adhesive in the center of insulation (polystyrene) x 3.3 0.4 0.3 0.3 1.5 3.2 0.6 1.3 0.40 1.3 2.8 1.36
33 D3a D Insufficient adhesive surface area x x 2.6 1.9 1.0 0.5 0.6 3.1 0.3 1.9 0.41 2.8 2.5 2.84
34 D3b D Insufficient adhesive surface area x 3.2 0.9 0.7 0.4 0.3 2.9 0.2 1.2 0.39 2.8 2.5 2.67
35 D4 D Adhesive is not rubbed into insulation plate (mineral wool) x 2.4 0.0 0.0 0.0 0.6 2.6 0.0 1.2 0.28 2.0 3.0 1.66
36 D5 D Adhesive is not treated with notch towel (mineral wool) x 2.9 0.5 0.4 0.0 0.1 1.9 0.1 1.1 0.31 2.3 3.0 2.14

Sustainability 2018 , 10 , 3900 21 of 26
T able A3. Data for Equation (3).
Sequence ID Layer Description ETICS 1 ETICS 2 ETICS 3 SC1 SC2 SC3 SC4 SC5 SC6 SC7 SC8 SV OV DV TRPN
37 D7a D W orking time of the adhesive is exceeded x x 2.8 0.5 0.3 0.2 0.3 2.7 0.3 1.7 0.34 1.8 2.6 1.60
38 D7b D W orking time of the adhesive is exceeded x 4.0 0.5 0.3 0.2 0.3 3.3 0.3 1.9 0.44 1.8 2.8 2.24
39 D8a D Low pressur e during application of insulation plates x x 1.9 0.6 0.3 0.3 0.4 2.1 0.4 1.0 0.25 2.7 3.0 2.02
40 D8b D Low pr essure during application of insulation plates x 3.4 0.8 0.4 0.2 0.3 2.7 0.3 1.6 0.40 2.0 3.0 2.38
41 D9a D Large unevenness of the adhesive layer x x 1.9 0.4 0.4 0.3 0.1 1.8 0.0 1.3 0.23 1.7 3.5 1.35
42 D9b D Lar ge unevenness of the adhesive layer x 2.9 0.4 0.4 0.3 0.1 2.4 0.0 1.3 0.32 1.7 3.5 1.87
43
M9a
D Low temperature (freezing) during application and/or curing process x x 3.5 0.4 0.0 0.1 1.1 3.2 0.4 2.5 0.42 1.4 2.2 1.31
44
M9b
D Low temperature (freezing) during application and/or curing process x 4.6 0.4 0.0 0.1 1.3 3.7 0.4 2.7 0.52 1.6 2.4 2.01
45
M10a
D High temperature (hot) during curing process x x 2.6 0.3 0.0 0.1 0.5 2.3 0.2 1.7 0.31 1.8 2.6 1.43
46
M10b
D High temperature (hot) during curing process x 3.6 0.3 0.0 0.1 0.8 3.0 0.2 1.9 0.40 1.8 2.6 1.89
47
M11a
D Low humidity (dry) during curing process x x 2.6 0.0 0.0 0.0 0.4 1.9 0.0 1.0 0.26 2.3 3.0 1.82
48
M11b
D Low humidity (dry) during curing process x 3.7 0.0 0.0 0.0 0.4 2.4 0.0 1.4 0.37 2.3 3.0 2.56
49 M8 D Not recommended ingredients added to the mixtur e x x x 3.4 0.9 0.0 0.0 1.9 3.9 0.0 2.9 0.47 1.8 2.6 2.18
50 I1 I Polystyrene is exposed to ultraviolet (UV)-radiation for an extended period x x 3.3 0.4 0.2 0.1 0.9 3.3 0.7 1.6 0.40 1.3 1.4 0.70
51 I2 I
Insulation plates are installed shortly after manufacturing (unfinished dif fusion process
x x 1.4 0.4 0.8 0.5 1.0 2.8 0.4 2.1 0.26 1.8 3.5 1.61
52 I3a I Mineral wool insulation plates have very high relative humidity (are wet x 2.4 0.3 2.4 0.3 1.3 2.1 0.8 0.9 0.30 1.2 2.4 0.87
53 I3b I Insulation plates which have very high relative humidity (wet) x x 0.8 0.6 1.4 0.2 1.0 0.6 0.8 0.2 0.14 1.5 3.0 0.61
54 I4 I Continuous gaps between substrate and insulation material x x x 2.2 3.3 4.3 2.2 2.1 3.7 2.0 1.3 0.53 1.4 3.2 2.38
T able A4. Data for Equation (4).
Sequence ID Layer Description ETICS 1 ETICS 2 ETICS 3 SC1 SC2 SC3 SC4 SC5 SC6 SC7 SC8 SV OV DV TRPN
55 I5 I Corners of neighboring insulation plates are cr ossed or too close x x x 1.0 0.1 1.0 0.3 1.8 2.7 0.2 2.1 0.23 2.3 1.3 0.65
56 I6 I Corners of the openings have crossed joints x x x 1.4 0.1 1.3 0.1 2.2 3.1 0.5 2.3 0.28 2.8 1.2 0.93
57 I7 I
Insulation plates joint width of neighboring insulation plates is too wide
x x x 1.0 0.0 2.0 0.6 1.6 2.4 0.4 1.0 0.21 1.5 1.0 0.31
58 I8 I Large height dif ference between neighboring insulation plates x x x 0.6 0.1 0.8 0.3 1.8 2.6 0.5 1.8 0.20 2.0 2.0 0.78
59 I9 I Broken ar eas of the insulation plates are not filled with same material x x x 1.0 0.6 1.8 1.0 1.6 1.9 0.0 1.2 0.22 2.3 1.3 0.61
60 I10 I Missing or narrow fire reluctant areas x x 0.1 4.9 0.1 0.1 0.1 0.3 0.1 0.1 0.22 1.5 1.3 0.41
61 A1 A Increased diameter of drilled anchor hole x x 4.0 0.7 0.3 0.2 0.6 2.4 0.3 1.4 0.42 1.5 3.0 1.91
62 A10 A Hole of the anchor is not cleaned x x 2.3 0.3 0.0 0.0 0.0 1.5 0.0 0.7 0.24 1.3 2.3 0.73
63 A5 A Location of anchors is not as foreseen x x 2.5 0.5 0.0 0.1 0.1 1.4 0.0 1.1 0.26 1.7 1.3 0.58
64 A3 A Decreased number of anchors in the continuous areas x x 3.5 0.4 0.1 0.1 0.1 2.3 0.0 1.1 0.36 2.5 1.3 1.11
65 A8 A Decreased number of anchors in the corner areas x x 3.6 0.6 0.2 0.1 0.6 2.6 0.4 1.6 0.39 1.7 1.3 0.87
66 A9 A Usage of unsuitable anchor type x x 4.2 0.6 0.1 0.1 0.5 2.9 0.4 1.8 0.45 2.2 2.4 2.39
67 A2 A Decreased diameter of anchor plate x x 3.4 0.3 0.1 0.1 0.3 2.1 0.2 0.9 0.34 1.3 1.0 0.45
68 A6 A Anchor plate is installed too deeply into insulation material x x 1.1 0.1 1.0 0.3 1.6 2.6 0.2 1.4 0.22 2.4 1.0 0.53
69 A7 A Anchor plate is placed too high on the surface of insulation material x x 1.7 0.1 0.4 0.2 1.0 2.4 0.3 1.6 0.25 1.8 1.0 0.43
70 R1 R External layer of the insulation plate is too smooth, reduced adhesion x x 3.5 0.0 0.0 0.0 1.7 3.3 0.7 1.3 0.40 2.0 3.0 2.37
71 M1c R Unsuitable material storage conditions x x x 4.0 0.0 0.0 0.0 2.6 4.3 0.0 3.0 0.49 1.0 3.0 1.48
72 M2c R The mixing procedur es do not remove clots x x x 3.1 0.0 0.0 0.0 2.1 3.3 0.0 2.6 0.39 1.2 2.2 1.03

Sustainability 2018 , 10 , 3900 22 of 26
T able A5. Data for Equation (5).
Sequence ID Layer Description ETICS 1 ETICS 2 ETICS 3 SC1 SC2 SC3 SC4 SC5 SC6 SC7 SC8 SV OV DV TRPN
72 M2c R The mixing procedur es do not remove clots x x x 3.1 0.0 0.0 0.0 2.1 3.3 0.0 2.6 0.39 1.2 2.2 1.03
73 M3c R High share of kneading water x x x 3.8 0.0 0.3 0.0 2.9 3.8 0.3 3.0 0.47 1.8 2.2 1.86
74 M4c R Low share of kneading water x x x 3.1 0.4 0.0 0.1 2.4 3.2 0.4 2.8 0.42 1.4 2.6 1.52
75 R6 R Thin mortar layer x x x 3.0 2.5 1.1 1.3 3.6 4.3 1.0 3.6 0.58 2.8 2.0 3.19
76 R2 R Decreased overlap of the mesh x x x 2.2 0.7 0.4 0.1 1.7 3.2 0.8 2.4 0.36 1.8 3.0 1.88
77 R3 R Folded mesh x x x 1.4 0.4 0.4 0.0 0.9 2.6 0.4 2.1 0.25 1.0 2.5 0.64
78 R4 R Missing diagonal mesh x x x 2.1 0.5 0.4 0.0 1.2 3.1 0.6 2.3 0.33 2.0 2.5 1.64
79 R5 R Mesh not filled with mortar , placed on the edge of the layer x x x 3.0 0.7 0.1 0.4 1.9 3.6 0.0 2.1 0.41 2.0 2.3 1.93
80 R7 R Layer is not applied in wet to wet conditions x x x 2.6 0.0 0.3 0.0 2.3 3.0 0.4 2.7 0.35 2.5 3.0 2.66
81 R8 R Usage of not compatible mesh x x x 3.2 0.9 0.4 0.0 1.4 3.9 0.5 2.9 0.46 1.4 3.0 1.92
82 M9c R Low temperature (fr eezing) during application and/or curing process x x x 4.8 0.8 0.3 0.3 3.3 4.7 0.6 4.0 0.63 1.8 1.8 2.05
83
M10c
R High temperature (hot) curing conditions x x x 3.5 0.3 0.0 0.1 2.5 3.6 0.4 2.8 0.45 2.2 1.8 1.77
84
M11c
R Low humidity (dry) curing conditions x x x 3.5 0.0 0.0 0.0 3.0 3.6 0.0 3.1 0.45 2.0 1.5 1.34
85
M12c
R Usage of winter mixtures during unsuitable weather conditions x x x 2.4 0.0 0.0 0.0 2.6 3.2 0.0 1.8 0.33 1.0 3.0 0.98
86 X6 X Shock resistance solution is not used (i.e., no double reinfor cement mesh, corner details
with metal or additional protective plate installed) x x x 1.9 0.3 0.1 0.4 1.4 3.7 0.2 1.1 0.30 2.6 2.0 1.56
87 F2 F Reinforcement mixture or primary coat is not cur ed x x x 1.7 0.0 0.2 0.0 1.8 2.8 0.6 1.3 0.25 2.0 3.0 1.51
88 F1 F Missing primer if requir ed x x x 1.5 0.1 0.2 0.0 1.5 2.5 0.2 0.8 0.22 1.4 2.2 0.67
89
M1d
F Unsuitable material storage conditions x x x 4.3 0.4 0.0 0.1 3.4 4.4 0.9 2.9 0.56 1.0 2.6 1.45
90
M2d
F The mixing procedur es do not remove clots x x x 3.6 0.0 0.0 0.0 3.4 3.8 1.0 2.2 0.45 1.0 2.0 0.91
91
M3d
F High share of kneading water x x x 3.2 0.7 0.3 0.2 4.3 4.5 1.2 3.3 0.51 0.5 1.7 0.43
T able A6. Data for Equation (6).
Sequence ID Layer Description ETICS 1 ETICS 2 ETICS 3 SC1 SC2 SC3 SC4 SC5 SC6 SC7 SC8 SV OV DV TRPN
91
M3d
F High share of kneading water x x x 3.2 0.7 0.3 0.2 4.3 4.5 1.2 3.3 0.51 0.5 1.7 0.43
92 F3 F Thick render layer/differ ences in thickness x x x 0.9 0.1 0.7 0.4 1.3 2.3 0.1 1.1 0.18 0.7 3.0 0.37
93 F4 F Thin render layer x x x 1.6 0.6 0.7 0.6 2.6 2.7 0.4 1.3 0.28 1.5 1.7 0.71
94
M9d
F Low temperatur e (freezing) during application and/or curing process x x x 4.5 0.5 0.3 0.4 3.4 4.7 0.6 3.4 0.60 1.5 1.0 0.89
95
M10d
F High temperature (hot) curing conditions x x x 3.5 0.3 0.0 0.1 2.5 3.5 0.3 2.5 0.44 2.2 1.4 1.35
96
M11d
F Low humidity (dry) curing conditions x x x 3.6 0.0 0.0 0.0 3.0 3.6 0.0 2.6 0.45 2.5 1.5 1.67
97 X1 X Structural expansion joint is not installed/finished properly x x x 1.5 0.3 0.5 0.3 2.0 2.8 0.3 3.0 0.29 1.4 1.8 0.72
98 X2 X W indowsill not appropriately finished (i.e., curved upwards, pr oper sealants) x x x 2.1 0.6 1.1 0.3 4.0 4.1 1.1 1.7 0.39 3.6 1.6 2.26
99 X3 X Unsolved rainwater drainage (i.e., drainpipe or drip profiles not used) x x x 2.6 0.3 2.0 0.1 4.3 4.3 2.3 2.6 0.46 3.0 1.2 1.65
100 X4 X Fixed frame connection is not finished accurately (i.e., missing sealants) x x x 1.6 0.5 1.7 0.5 3.5 3.5 0.9 1.5 0.33 3.2 1.8 1.92
101 X5 X Roof edge covers are not installed correctly (i.e., vertical detail too short) x x x 1.0 0.1 0.9 0.1 2.9 3.3 0.6 0.4 0.23 2.6 2.0 1.17
102 X7 X Unfinished penetrations through the system (i.e., fixed without sealants) x x x 1.8 1.3 1.4 0.8 3.9 3.9 1.3 1.4 0.39 3.4 1.2 1.59
103 X8 X Unsuitable plinth detail solutions (i.e., incorrect fixing, overlapping of details) x x x 1.7 0.3 0.8 0.1 2.7 3.0 0.4 1.0 0.28 2.6 1.4 1.02

Sustainability 2018 , 10 , 3900 23 of 26
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Why organizations use Identific for document trust, entry 76

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