Roof and climate: Are there lines which can draw on Europe a progressive change of the roofing parameters?

0 FINAL REPORT 01/07/2015 PROF. DR. ANDREW PETERSEN BSc, PhD, CEng, MICE DEPARTMENT: INTERNATIONAL CIVIL ENGINEERING PILAR HUERTA NAVARRO ID: 913388 ROOF AND CLIMATE Are there lines which can draw on Europe a progressive change of the roofing parameters? ARGUING A PROPOSAL 1 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 ACKNOWLEDGEMENTS I wish to express my sincere thanks to Dr. Professor Andrew Petersen, for providing me with all the necessary facilities for the research, thereby transmitting me his passion and dedication for the good work and his motivation for carry out it. Despite this paper wouldn’t have been possible without the support of my colleagues from Valencia, Pablo Tarazón and Inés Gran, all together we have achieved the aim of what it means for both discipline and independence to do the research with the condition to make in another language, and to get the sure persons, in who we have become. Finally I would like to say thanks to my family for the opportunity to study in another country, for the sustained support and the confidence in me. Thanks too to the Polytechnic University of Valencia for fight the long for finally I could realize my foreigner experience. Here I finish five years of effort, work and especially very good friendships, who I will never forget. “Now is a time for defiance” 2 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 ABSTRACT The roof is considered the element of house through it the majority of the heat lost are produced. With the proper conditioning can be achieved the thermal comfort indoor. To carry out the research has been necessary to find the parameters which draw from the climate, and which can be modified regarding of it. To carry out it as already mentioned, is necessary a previous knowledge on Europe temperatures. With the put in practice of the roofing requirements in each country or area, and the results of comparison, it is possible to see a lineal development from North to South or vice versa of all of the parameters acting on it. Orientation, climate, slope, winds, reflection and color, thermal analysis, ventilation, materials, insulation and cool loads have been studied accurately to argue the proposal. 3 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................................ 1 ABSTRACT ................................................................................................................................. 2 TABLE OF CONTENTS ................................................................................................................ 3 LIST OF TABLES ......................................................................................................................... 5 LIST OF FIGURES ....................................................................................................................... 6 CHAPTER I -INTRODUCTION ........................................................................................... 7 1.1. Background ............................................................................................................ 7 1.2. Purpose ................................................................................................................... 8 1.3. Aim and Objectives ............................................................................................... 9 1.4. Scope of the Research ......................................................................................... 9 1.5. Chapter Summary ................................................................................................. 9 CHAPTER II – LITERATURE REVIEW ........................................................................... 11 2.1. Overview ................................................................................................................... 11 2.2. Analysis and Adaptation ......................................................................................... 11 2.3. Chapter Summary ................................................................................................... 24 CHAPTER III - METHODOLOGY ..................................................................................... 25 3.1. Methodology Scheme ............................................................................................. 25 3.2. Climate as a Source ................................................................................................ 25 3.3. Chapter Summary ................................................................................................... 26 CHAPTER IV – DATA ANALYSIS ............................................................................................... 28 4.1. Data Presentation ....................................................................................................... 28 4.2. Chapter Summary ....................................................................................................... 32 CHAPTER VDISCUSSION OF RESULTS ................................................................... 33 5.1. Topics of the research ................................................................................................. 33 5.2. Orientation ................................................................................................................ 33 5.5. Reflection. Color .......................................................................................................... 34 5.3. Materials ..................................................................................................................... 36 5.4. Economic Requirement ............................................................................................... 38 5.6. Insulation .................................................................................................................... 38 5.7. Slope ............................................................................................................................ 39 5.8. Climate ........................................................................................................................ 42 4 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 5.9. Ventilation ................................................................................................................... 43 5.9.1. Ventilation in warm climates .............................................................................. 44 5.9.2. Ventilation in cool climates ................................................................................ 44 5.10. Chapter Summary ..................................................................................................... 44 CHAPTER VI – CONCLUSIONS AND RECOMMENDATIONS ..................................................... 45 6.1. Conclusions ................................................................................................................. 45 6.2. Recommendations ...................................................................................................... 46 REFERENCES ........................................................................................................................... 48 ATTACHED .............................................................................................................................. 50 5 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 LIST OF TABLES Table 1 Roofing Color and Cooling Loads. (Bliss, 2015) .........................................13 Table 2 Reflectance of Roof Materials (A Green Affordable Housing, 2005) ...........15 Table 3 Color Materials (A Green Affordable Housing, 2005) .................................15 Table 4 Constructive characteristics of roofing materials. Guimaraes (2008) ..........16 Table 5 Computed properties of untreated and treated roof section .......................18 Table 6 Asphalt shingle application. (Oregon Structural. Speciality Code, 2004) ....18 Table 7 Clay and concrete tile attachment (Oregon Structural. Speciality Code, 2004) ......................................................................................................................19 Table 8. Clay or concrete roof tile with projecting anchor lugs (Oregon Structural. Speciality Code, 2004) ............................................................................................19 Table 9 Interlocking clay or concrete roof tile with projecting anchor lugs. (Oregon Structural. Speciality Code, 2004) ...........................................................................20 Table 10 Slate shingle (Oregon Structural. Speciality Code, 2004) ........................20 Table 11 Slopes Scheme, Source; The author 2015) .............................................40 6 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 LIST OF FIGURES Figure 1 Computed values of room temperatures for summer conditions inside a normal sized building (4mx4mx3m). Bansal, Grag, and Kothari (2004) ...................12 Figure 2 Computed values of room temperatures for mil winter conditions in a normal sized building (4mx4mx3m). Bansal, Grag, and Kothari (2004) ...................13 Figure 3 Expectations connection between climate and roofing design ..................25 Figure 4 Observing the spatial distribution of the regional wind regimes in terms of full-load hours . Source: University of Strathclyde Engineering ESRU(2009) ...........................................................................................................28 Figure 5 Annual full load hours of optimally inclined PV modules. Source: (Held 2011) based on data from Suri et al. (2007) and a performance ratio of 0.75 ..........29 Figure 6 Adapting roofing slopes regarding regional wind regimes.Source: University of Strathtclyde Engineering ESRU. .........................................................29 Figure 7 Adapting roofing slopes regarding regional wind regimes. Source: University of Strathtclyde Engineering ESRU. .........................................................30 Figure 8 Figure 4. Roofing Materials in Europe. Source: Roof coverings and best practices(2012) .......................................................................................................31 Figure 9 Minimum and máximum temperaturas in Europe. Source. (Organización Meteorológica Mundial, 2015), (Köppen, 2015) ......................................................31 Figure 10................................................................................................................31 Figure 11 Ventilations Size (Pickett, 2015) .............................................................43 7 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 CHAPTER I -INTRODUCTION This report will propose research of roofing types in Europe and how the choice of the roofing materials are affected by the climate avoiding losing heat by the roof in different climate conditions. This study investigates the effect of the roofing materials, insulation, roofing slopes, and the surface color of the roof on the maximum indoor temperature of a house located in a three different climatic regions. However, the use of appropriate materials and insulation could afford significant improvement, which could be further enhanced with the use of light colors for the roof surface. 1.1. Background First, it must also pointed, despite of the Common Market, Europe is still a patchwork quilt of separate countries with differing local and imported building materials. This has led to differing traditions of skill and habits of construction, and without a common language to facilitate pan-Europeanism in building technology. (A Green Affordable Housing, 2005). Historically this has resulted in quite sharp architectural differences in handling weather-casting systems of sloped roofing obvious, and the demands of historic conservation keep the traditional skills and materials alive. But even in the less obvious early development of waterproof roof systems there were national differences. More recently, the advent of multi-national roofing industries and the almost universal need to conserve energy have been strong internationalizing influences, but even these have not prevailed entirely against some national prejudices and protectionist instincts. There are, of course, climatic differences familiar to everyone, but these exists in any large land mass. What I have been delineating is the contrast in Europe, where one language and economic commonality prevails. These obstacles do not ease the task of reporting on European roofing Is a generally held view that traditional architecture is more climatic conscious than contemporary architecture. This subject has been dealt with by a number of researchers. As a result, it is considered useful to study traditional architecture so that 8 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 important lessons can be identified which can be applied in improving the current architecture (Malama & Sharples, 1997). The present study set out to investigate traditional and contemporary housing thermal performance in Europe. It reports on measurements from temperatures average during last 10 years. It looks at a typical traditional house and analyses their thermal response to the climate. It finally compares the results of the climatic study with the results of a thermal comfort. This work is a research project which is studying the thermal performance of housing in Europe. Presented here are the initial results of the project. Roofing is often ignored as an energy efficient component of a house, but it has a profound effect on the other systems, especially air conditioning. An efficient total roof system can lower the energy required for cooling’s home by 30 percent or more. Roof is the major contributor of heat gain in buildings. Theoretical studies are available to determine heat flow through different building components. But a very few studies are available which deal with experimental investigation. High summer temperature ranging from 20-35° C in southern part of Europe necessitate cooling of buildings to provide a comfortable and workable living environment indoors. As such air conditioning is necessary in South Europe during summer months of the year. For non-conditioned residential and other types of buildings, peak temperature is reduced by using roof insulation. The use of thermal insulation to minimize solar heat gain in summer and heat loss in winter. (Suman & Srivastava, 2008). Jean Dollfus in his Collection of Samples of Homes explains the relation between climate and architecture. He affirms that the main aim of the building is the research for optimal conditions of thermal comfort. According to his analysis, the constructive typology will be defined because climate regions and not for the limit region. Roof color plays some role in attic temperature, but its role isn’t nearly as significant as roof material and attic ventilation. Depending on the climate, a light or dark roof in a residential application may work in favor of, or combat, the primary conditioning needs (heating or cooling). If it interior comfort the key point to resolve, then adequate insulation in the roof or attic will have the biggest effect on thermal resistance. (Best Practices Guide to Residential Construction, 2015). 1.2. Purpose 15 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 The data collected from this study to define the slope are; sun index of reflectivity higher or equal to 70 to slopes lower than 15% and, the sun index of reflectivity 29 to highest slopes >15%. Table 2. Reflectance of Roof Materials (A Green Affordable Housing, 2005) Table 3. Color Materials (A Green Affordable Housing, 2005) The climate is determinant in decisions about the roofing, it means the linkage between the climate and architecture at the search for thermal comfort optimal conditions. (Mercon, 2008) 16 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 This paper claim that architectural typology is defined by climatic zones. In hot-humid areas, the characteristics of architecture are: light, well ventilated, protected in all solar radiation directions and without thermal inertia. With everything, Mercon (2008) confirms the positioning of the building need not be necessarily perpendicular to the direction of the winds. Machado, Ribas and Oliveira (2008) affirm that the rotations 20 ° to 30 ° in relation to the prevailing summer winds are also recommended, using resources to ease crossways ventilation. This has been used to carry out to reach an orientation roofing design. Table 4. Constructive characteristics of roofing materials. Guimaraes (2008) The major work of W.Köppen, describes a system based on the concept that native vegetation is the best expression of climate. Thus, climates boundaries have been selected with vegetation distribution in mind. It combines average annual and monthly temperatures and precipitation, and the seasonality of precipitation. Köppen assigns generally Group C to Europe. (Wikipedia, 2015) The information has been completed with an official weather forecast (Organización Meteorológica Mundial, 2015) focused only in Europe, for what, more exactly the temperatures have been achieved. With this temperatures has been possible draw three lines in Europe, which have divided in three areas to resolve the problem statement. The houses of Europe are generally roofed with rain-shedding tile systems, traditionally of clay, because good clays are abundant all over Europe. However, 17 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 cement has captured a share of the market in some areas during the past years. They claim that the wood shingle of North America never took hold in Europe. A large proportion of the publication focuses sheet metals, lead, zinc, aluminum and stainless steel as second category of weather-casting roofing. He maintains mostly of them are used on buildings other than houses and they can do their job successfully even at very shallow slopes. (Allen & Allen, 2014). This proposal has helped to realize the material distribution, adding information on local materials, and others which have been rejected, due to, they are not used in dwelling roofs. The potential environmental impact of rom air conditioner carried out for the European Commission in support of the Energy-using Products Directive plays a fundamental role. This paper assesses the likely market, the consequent environmental impacts and the scope for reducing the global warming impacts by the use of “best available” or “least life cycle cost” technologies. The analysis reflects the increased insulation levels of new buildings, compared to the existing stock, there is no assessment of the possible impact of provision of better shading. Spain, Italy, France and Czech Republic would be the countries with more sales than removals. (Pout & Hitchin, 2015). The market investigation all over Europe has served to analyze which countries demand for air-condition. In this way and together with the climate dates it will be able to achieve to make a detailed analysis of the insulation regarding of climate and the temperature indoor. Effect of Expanded Polystyrene and Fiberglass thermal insulation on roof has been studied with a view to reduce heat gain and improve thermal performance. The experiment were conducted by treating one roof with thermal insulation while the other was kept untreated. Indoor and outdoor air temperature, roof and ceiling temperature and relative humidity in terms of dry bulb and wet bulb temperature were recorded during peak summer period. They found that indoor environment of untreated room was in the discomfort range during the most of the hours whereas indoor temperature of room treated was within comfortable range with a ceiling fan providing wind speed around 9m/s. 18 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 Table 5Computed properties of untreated and treated roof section It have approached to the study that the use of thermal insulation can minimize solar heat gain in summer and heat loss in winter through roof. (Suman & Srivastava, 2008) Distribution of the regional wind regimes in terms of full-load hours have been adapted to establish roofing slopes regarding regional wind regimes. (University of Strathtclyde Engineering, 2009) The information collected has been used to make a prior distribution of Europe among three areas with three different slopes: higher, low and steepest slopes. In materials section, roof-covering materials shall be studied to apply and install in accordance with the provisions of requirements for roof coverings, where is analyzed each material (Asphalt singles, valley lining material, concrete roof tile, clay and concrete tile, metal roof coverings, slate shingle head lap and wood shingle and shake installation) (Oregon Structural. Speciality Code, 2004). Between the different section of the publication, Roof Drainage, Performance Requirements, Fire Classification, Materials and Requirements for roof coverings. In the study have been used the last two, materials and requirements for roof coverings. With them together with data from slope, whose requirements depend of material, it has been possible get a distribution of the materials in Europe. Table 6. Asphalt shingle application. (Oregon Structural. Speciality Code, 2004) 19 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 Table 7. Clay and concrete tile attachment (Oregon Structural. Speciality Code, 2004) Table 8. Clay or concrete roof tile with projecting anchor lugs (Oregon Structural. Speciality Code, 2004) 20 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 Table 9 Interlocking clay or concrete roof tile with projecting anchor lugs. (Oregon Structural. Speciality Code, 2004) Table 10Slate shingle (Oregon Structural. Speciality Code, 2004) Davies (2013), in his guide to roof construction, stablishes roof pitch in the UK for a traditional house, which will be 40°-50° but at the extreme can go up to 70°. Part of the choice of pitch is down to the architect. As well as the visual appearance, the choice of roof pitch is influenced by the materials to be used and the resulting overlap required if roof tiles are used. An example is proposed; thatched roofs are often 45° or more whilst a slate tile roof can be much flatter at say a 35° pitch if desired. In areas of high snow all then the roof pitch can be much greater, to allow the snow to fall off the roof rather than settle and build up on the roof. Roofs with pitches of 10°-20° are often called low pitched roofs and special considerations need to be made, particularly on the overlap between tiles to avoid water being blown into the roof by the wind. (Davies, 2013) It proposes different material used for the outer layer of pitched roofs, just as, once more, it helps to understand that in cold climates the slopes will be highest than in warm climates. One point that Davies attaches is the concept of the high slope taking in account the height of roof due to the snow. Light colored roofs in warm climates and dark colored roofs in cold climates are most compatible with the particular climate’s primary type of conditioning (cooling or heating). The higher the solar reflective value, the more efficient the product is in reflecting sunlight and heat away from the building and reducing roof temperature. This is particularly important in warm areas where peak load is a concern. In warm and sunny climates, highly emissive roof products can help reduce the cooling load on the building by releasing the remaining heat absorbed from the sun. On the other 21 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 hand, there is also evidence that low emissivity may benefit those buildings located in colder climates by retaining heat and reducing the heating load. A poorly constructed attic or roof assembly can lead to excessive energy losses, ice dams, mold, rot, and lots of unnecessary homeowner angst. In a cold climate, the primary purpose of ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow and to vent any moisture that moves from the conditional living space to the attic. In a hot climate, the primary purpose of ventilation is to expel solar-heated hot air from the attic or roof to reduce the building’s cooling load and to relieve the strain on air-conditioning systems. In mixed climates, ventilation serves either role, depending on the season. For best results, provide between 50% and 75% of the ventilation space at the eaves; a 60/40 split is a good sweet spot. (Lstiburek, 2011) Apart of the information about the location and final area of the ventilation, this proposal continue with the information about the color and reflection, differencing among warm and cold climates. The optimization of the indoor climate is the most important and long recognized role of the architect. In contrast, although not entirely neglectful of climatic considerations, urban planners have, until comparatively recently, only rarely considered climatic among the several constraints upon urban design. (Chandler, 1976). Thus, the modification exercised by the local orography upon the regional climate are of fundamental importance and have to be carefully considered, for substantial differences in radiation receipts and losses, temperature. (Geiger et al. 1969) This paper involves air environment from another angle, the air above cities is infused with solid, liquid and gaseous pollutants; temperatures are generally higher in cities than in their rural surrounds; it provide relative humidities, which are most frequently lower though absolute humidities can sometimes be higher in urban than in rural areas; precipitation tends to be enhanced within or the lee of cities; visibilities are poorer and radiation receipts are also lowered by the pollution. Until this point the differences of climate among urban and rural areas have been not considered. 22 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 Wise’s Effect studies the influence of the slope of the roof of the highest building influenced by the speed wind which affect on the lower level, this study is carried out through some tests. These tests may include wind tunnel tests, where the slope of the highest building was tested with three numbers. Of this study it can affirm the relation between the slope and wind speed on the lower level. With lean angles among 24º and 45º wind force is set to increase. (Apcarian, Walter, & Lassig, 2004). Here is established that winds higher to 5 m/s will impact negatively to the people's comfort. “Generally, roof color plays some role in attic temperature, but its role isn’t nearly as significant as roof material and attic ventilation“. A cooler attic or roof means there is a bigger temperature difference across the insulation, which results in faster heat loss. Therefore, in residential applications, dark colored roofs may be better for northern climates. This concept has contributed to the research to divide among cool and heat roof, in other words black and white. (Energy Options Explained (EOE), 2015). “Roof Colors”, Energy Options Explained (2015) finds the insulation associates with the reflection (light-colors), because only the suitable thickness will have the biggest effect on thermal resistance. With this information it has been able to achieve the correct insulation distribution. Attic temperatures can vary as much as 20 to 40 degrees F (-6ºC to 4,5ºC) which in turn can reduce energy consumption by 20%, (Builders, Dealers, DIY and Framers, 2014). The study of this corporation ensures that radiant absorptivity of the shingle is a predominant factor indicating peak roof sheathing temperatures. Besides of data collected of roofing colors from the website, it provides the results with a study in which changing black and white shingles on the same roof, it made with panels under them, the temperature of the attic in a sunny day the black-shingled roofs were 10ºF to 15ºF warmer than the identical white-shingled. However, during the evening, the black-shingled roofs also tended to lose heat faster than white. In obtaining equilibrium with ambient outdoor temperature, both, generally experienced similar nighttime temperature profiles. 23 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 The information of Findlay Roofing Website affirms that roof ventilation is more important than shingle color if you are concerned about keeping roof and attic temperatures low in the summer. This approach, roof ventilation can be achieved through the combined use of ridge vents, soffit vents and other features. “Roof ventilation combined with attic insulation is the recipe for a cool house in the summer” (Findlay Roofing, 2015). In this way to develop the ventilation in European roofing it has taken in account the insulation regarding of the altitude. This article has helped to reach an agreement about to distribution the ventilation, then divide it in two parts, in warm and cold climates. More attic ventilation is good, roof vents are for warmer climates, roof vents remove warm air during the winter This are some topics which the author take into account to keep attic fresh with circulating air and to reduce moisture levels. (Pickett, 2015). The same at the previous case, this proposal has helped to understand the ventilation importance in the attics behavior. An indication of the BASIX classification for their roof tiles, which is split into ratings of light, medium or dark, depending on the tile’s solar reflectivity. Out of 22 concrete tile colors, only one was classified as light and four as medium. For terracotta tiles, out of the 17 choices none were light and only five were rated medium. “The part color plays here is that a dark roof in certain climates may mean that compliance would recommend a slightly higher R-value for their insulation, but it is not massive factor “. (Jewell, 2014). The recently appointed sustainability guide “Your Home” states that light colored roofs are estimated to reflect up to 70 per cent more than a dark roof. However, research the RTAA commissioned, found that light colored tiles yielded energy savings between 25-36 per cent compared to dark colored tiles. Heating season and two primary purposes of attic ventilation, removing moisture and ice dam prevention, are treated in this website. As outdoor temperature drops we add heat and add moisture to our homes. In the winter, home acts like a giant smoke 24 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 stack: cold air comes in through the basement and rises through the house into the attic. (Energy Smart Home Performance, 2015) Moisture in the attic is drawn to cold surfaces just as it’s drawn to your windows. When those surfaces get wet, they rot and mold ensues. The “theory” behind attic ventilation is to give that moisture a place to escape before it causes mold, mildew, rot, or other problems. The ventilation reduces peak attic temperatures by less than 10 degrees and changing from dark roof color to light color can have 6-7 times greater impact. The good ventilation can significantly reduce the temperatures in the houses. Simpler and cost effective options like roof ventilators need to be explored for the settlements about minimize energy consumption, depending on passive cooling principles in addition to cool roofs. (Thermal Comfort, 2015). Even though the need for space cooling has increased and growing incomes and aspiration have resulted in air conditioners replacing fans in most of the middle class houses, the article has provided for the research the needless to use air condition in cool climates. 2.3. Chapter Summary This chapter has contributed to develop and lay the foundations to argue the proposal. The main sources of inspiration for this research can be collected in a group of twenty seven, within which there are two main proposals – Thermal Comfort and Architectural Typology in Hot Climates and Roof orientation, roofing materials and roof surface solour: their influence on indoor thermal comfort in war humid climates. The rest of them are literature which help to extend each integrated topic. Due to this paper is formed by the intervention of different parameters, has been necessary and very useful the integration of the little paragraphs deriving from internet websites. 31 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 Figure 8 Figure 4. Roofing Materials in Europe. Source: Roof coverings and best practices(2012) Figure 9 Minimum and máximum temperaturas in Europe. Source. (Organización Meteorológica Mundial, 2015), (Köppen, 2015) Figure 10. 4 8 15 ZONE 1 ZONE 2 ZONE 3 INSULATION -20 /<10 ºC ZONE 3 -7/ <22ºC ZONE 2 -3 />22ºC ZONE 1 32 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 4.2. Chapter Summary The results from an intensive research have been developed in this chapter. All of them has been presented on European maps, with a one aim. This aim has been to show how all the parameter and variables, deriving from the changing climate, vary leaving three clearly different areas from North to South. Arguing each topic and comparing the results obtained has been possible to achieve the first idea on the distribution and change. Knowing that all factors change at the same time in the lines before mentioned, is possible to suggest the perfect conditions for a roof and attic work according with the specific influences upon them, in other words, standardised proprieties. 33 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 CHAPTER VDISCUSSION OF RESULTS 5.1. Topics of the research Maria Guimares (2008), in her strong proposal suggests roofing material, roofing color and orientation like the most important factor indicating peak roof sheathing temperatures. Against her proposal the article from the Norbord (2014), ensures that radiant absorptivity of the shingle is predominant factor indicating it. Giovani (2008), however mentioned that the effect of external color on room air temperature depends on various other parameters also, particularly the heat resistance and heat capacity of the building (construction). It was observed that for low U value building with high thermal capacity, the effect of external color is not so significant as for a low thermal resistance and low heat capacity building. Finally Marcus Pickett (2015) in his article agree with good roof ventilation can increase energy efficiency during the summer, but sun exposure and insulation are considered by the author like a two variables exponentially more important to overall energy efficiency than ventilation. In the guide “Best Practices Guide to Residential Construction”, Federal Emergency Management Agency (2009) is completed the idea of the roof color plays some role in attic temperature, but its role isn’t nearly as significant as roof material and attic ventilation. Depending on each climate, a light or dark roof in a residential application may work in favor of, or combat, your primary conditioning needs (heating or cooling). If its interior comfort the key point to resolve, then adequate insulation in the roof or attic will have the biggest effect on thermal resistance. The las outlined was useful for starts the methodology research, finally the research was focused in reflection as an important aspect to consider. From this target point positioned in roofing color and its corresponding thermal analysis together the rests of the factors. Most of authors attach importance to the ventilation, in this research it has not been specially considered until the last research which has been found about. Currently, the opportunity to contain ventilation like an important variable would be studied to future researches. 5.2. Orientation 34 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 Jayasinghe, Attalage and Jayawardena (2003) in his article consider seriously the importance of the orientation of roof acting simultaneously with the roofing materials and colors. Machado, Ribas and Oliveira (2008), with their intervention in the proposal of Maria Guimaraes (2008) “Thermal Comfort and Architectural Typology in Hot-Humid Climates”, dare to take one more step and they propose the rotations, 20 ° to 30°, in relation to the prevailing summer winds, using resource to ease crossways ventilation. Conversely, from the experiment carried out by Suman and Srivastava (2008) about insulated roof for energy saving and thermal comfort could be conclude that the orientation of roof make a neutral effect relating to roof. They assert that is a negligible effect. Anyway in this research has not been considered the roofing orientation, because in when the wind direction is not coincident with the best solar orientation, ventilation must be prioritized due to ease of elements are used to shade against to drive the winds. Thus, in the first idea to develop the methodology was not took it in account. Priority has been given to attic ventilation. 5.5. Reflection. Color Givoni and Hoffman (1994), have carried out some experiments with different roof colors. The experimental measurements reported for two colors, namely white and grey, showed a difference of 3°C in the room air temperature when measured only 0,1m below the ceiling, while it remained only 1°C when measured 1,2m above the floor. The temperatures, as expected, were higher for grey colored enclosure. Independently of the different studies and experiments performed, all of the authors, even Bansal, Grag, and Kothari (2004), all their results agree on the idea of the change of the indoor temperature when the color roof is altered, approximately the number would be 7ºC. With the last result it has been able to do a pre-selection between cool climates and heated, in such a way, divide Europe in black roof where the temperature are lower, in our map between -20º to 10ºC, and white roof where are higher, where the temperature is between -3º-22ºC. In the area of the middle with temperatures among -7º to 22ºC the roof color defined is grey. 35 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 In the magazine A green Affordable Housing (2005), a cool roof is defined as one with a solar reflectance of at least 0,70 and an infrared emittance of at least 0,75. Regarding of sunlight intensity will be select roofing type. The shortage has been completed with the pick of datum of annual full load hours of optimally inclined PV modules in Europe (Held, 2011). Consequently if it looked the Table the materials with reflectance of roof materials at least 0,70 are white coating, ceramic, also metal and elastomeric. The last two have not been considered like a typically material used to residential buildings. Finally the South of Europe with warm climate will be built with Clay tiles which fulfil requirements successfuly. Table 1. Reflectance of Roof Materials (A Green Affordable Housing, 2005) As adaption to the study can be affirmed that since the “single-ply” classification includes both light and dark colored materials, products that are highly reflective it should be select also for heat island reduction and energy savings purposes. Maria Guimaraes (2008), in the main proposal used to carry out the research, supplies a table with a list of materials commonly employed in the contemporary architecture, and their characteristics among them, the reflection, figure 7. This characteristics table has been useful to present where necessary black and white roof is, but has been more profitable to decide and to discuss about the materials issue around Europe. That will be discussed subsequently. In the report of Energy Options Explained (2015) it has wanted to explain the basic physics behind light and colors; dark colors absorb more of the light spectrum, while lighter colors reflect more of it, but the visible light that is absorbed doesn’t just disappear into a material, it usually converts to infrared. The information here is not focuses just in color, but it is focused studying the combination of both, color and material to achieve thermal comfort. 36 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 In addition to the already presented “Builder, Delers, DIY and Framers” Norbord (2014), conclude with a concept which has been not contemplated before which determines the black color in cooler climates to help to melt winter snow. As already stated, this concept has been casted aside of any consideration for the research.Table 3. Builders, Dealers, DIY and Framers, (2014) claims that effect of external surface color on the room temperature inside a building will depend on other parameters: - Rate of air ventilation in the building - Direct solar radiation gain into the building These two effects have essentially been addressed in this study. The conclusions which have been adapted to the study are based on the concept that external surface color of a building envelope has been shown to have appreciable effect on the thermal behavior of a building measured in terms of the room temperature. 5.3. Materials The study of Jayasinghe, Attalage and Jayawardena (2003), compares the effect of aligning the ridge of a double-pitched roof in the east west or north-south direction, using different roof covering materials such as cement fibre sheets and clay tiles, 37 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 using different insulation materials such as aluminum foil and polystyrene, and having a light or a dark colored roof surface. Between the final conclusions the statements below have provided sufficient data, to affirm on roof covering material, the performance of clay tiles is marginally better than that of cement fibre sheets, and that the light color roof surfaces (white) can achieve indoor thermal conditions comparable to those of the insulation materials. Mariana Guimaraes (2008), with her study provides parameters of the contemporary materials, in this case, cover materials, which are the most used in the cotemporary architecture. With the level of tile’s absorption supplied and the incidence of the solar radiation will be possible to classify and then produce a new European map. It will be able to live up to the requirements for thermal comfort. The materials with the highest absorption, in other words with lower reflectivity, will be destined to countries with the low radiation and in the opposite case to intense radiations countries. These materials are asphalt, bitumen and concrete tiles. They are a fine-grained, foliated, homogeneous metamorphic rocks, and as such, is naturally resistant to moisture intrusion untreated. This means frost and freezing will not damage slate roofing. Slate roofing has many other advantages too. The weakness of the last paper is founded in the shortage of materials that she describes, because of it is only possible and applicable to the research the propriety of the clay tiles with an absorbency of 0.65. The last valor described is totally agree with the reflection of the data from “Roofing Materials for Flat Roofs”, A green Affordable Housing (2005), which determine for a cool roof a solar reflectance of at least 0,70. From this relationship is able to reach the first conclusion that clay tiles will be the properly material to warm climates with a high level of sunny light reflection. “Roof Assemblies and Rooftop Structures”, Federal Emergency Management Agency (2007), give some conclusions on asphalt and slate tiles what have helped to distribute them only on cool and very wet climates. The next lines describe features taken in account. -Shingles in general have a high emissivity but low reflectivity. 38 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 -White shingles only reflect up to 30% of the light that hits them. With any reflective surface, the reflectivity is reduced when the surface becomes dusty, dirty, or covered. Making again a comparison Guimares (2008) and “Roofing Materials for Flat Roofs”, A green Affordable Housing (2005), dark colors in the third area delimited, with black color, the area number 2 will have a reflectance between 30 and 70%. -Lighter colored shingles can last longer than dark shingles. This is because they absorb less light, and therefore aren’t prone to as much expansion and contraction as dark shingles are, causing less wear and tear. -Lighter colored shingles will however show their age, stains, and imperfections more noticeably than dark shingles. -Many studies show that black shingles reach temperatures 20-40 degrees higher than white shingles. However, attic temperatures will rise by only as much as 10 degrees Fahrenheit. Still, in a cooling application this 10 degree difference is of some worth when considering the temperature difference across a thermal boundary. The smaller the difference, the slower the heat loss. 5.4. Economic Requirement The first point it is thought to keep the temperature inside home, is controlling the temperature with air conditioning but it could assume a reis in the final costs of the bills electricity. Through the good realization of the roof it could decrease to 20%. That is the way that is exposed in the article “Roofing Materials for Flat Roofs”, A Green Affordable Housing (2005), and by Chandler (1976), furthermore the study done by Bliss (2015), determines a 17%. 5.6. Insulation Pout and Hitchin (2015) describe the results of surveys conducted in 12 mixed-mode buildings. The survey focus on areas indoor environmental performance, including thermal comfort and air quality. The data shows that only 11% of the 370 buildings, 39 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 most of which have conventional air-conditioning systems, are meeting the intent of the thermal comfort standards to achieve 80 satisfaction in the buildings. As is in the last outlined, this paper has contributed data for the research on insulation and where is necessary as his thickness. The weaknesses which has been found in this study is the focus on the use of insulation through the air conditioning datum, thus, it has been necessary to continue contrasting datum, it has been strengthened using an approach developed by Suman and Srivastava (2008), with it and their simulation in their experiment will be able to collect more precise statistics. The results of the simulation of Suman and Srivastava (2008) have been useful to adapt the data to achieve a classification on the thickness insulation in Europe. High summer temperatures 40°C necessitate cooling of buildings to provide a comfortable and workable living environment indoors. As such air conditioning is necessary. With a scale established of insulation thickness between the minimum 400mm to 1200mm. The assignment of it will regard the attic temperature and the difference of temperature between both spaces, indoor and attic indoor. To avoid heat lost, it will have to able to entail both, cool as heat roof, independently of the temperature. The warmest area has the minimum insulation, growing to 1200mm till the third part, the cold area. 5.7. Slope Davies (2013), in his guide to roof construction, stablishes roof pitch in the UK for a traditional house, which will be 40°-50° but at the extreme can go up to 70°, roof can be much flatter at say a 35° pitch if desired. In areas of high snow all then the roof pitch can be much greater, to allow the snow to fall off the roof rather than settle and build up on the roof. Roofs with pitches of 10°-20° are often called low pitched roofs and special considerations need to be made, particularly on the overlap between tiles to avoid water being blown into the roof by the wind. The data collected from A Green Affordable Housing, (2005) define the slope; sun index of reflectivity higher or equal to 70 to slopes lower than 15% and, the sun index of reflectivity 29 to highest slopes >15%. 40 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 Chandler (1976) suggest three topics differing in scale, they are regional climate, determined by synoptic factor; the modifying effects of the local orography and the selfinduced modifications of the buildings. Such differences are particularly important in high latitudes and high altitudes where major differences can accrue from relatively small changes in slope and aspect and these differences need to be carefully considered along with other criteria in deciding such matters as land use zoning for residential, commercial and industrial user. The authors consider wind speed as a factor to human comfort, but the research is not focus in it. The research has combined wind and slope, but not for goal of human comfort on the lower level (on the street), but also it adapts wind speed to achieve the suitable roofing construction and lay down a scale with for each winds conditions. To do so, it has entirely exploited the meteorological data of wind from Agency European of Meteorology (AEMET, 2015), and it has been contrasted with another website (Organization Meteorological Mundial, 2015) (University of Strathclyde Engineering ESRU, 2009). Thus it can establish de next parameters: Table 11. Slopes Scheme, Source; The author 2015) Despite of the last outlined, to check the wind force of Europe has been necessary to collect data from other threshold, like for sample: wind load of wind energy. Is huge suitable compare datum from countries which can benefit of the wind speed. (FEMA, 2015). It means that will have to provide their roof of appropriate slope. Another reason underlying to secure proper slope to get the good conditions in attic regarding of climate is working for reduce the heat island effect (Energy Options Explained (EOE), 2015), it means low slope roofs tend to be best, as they have a high reflectivity, with a high emissivity and will orient heat directly upward rather than at an angle. From the assembly of Oregon Structural it has been used the exact numbers corresponding to the requirement to the roof installation. The maximum basic wind speed and the roof height have been two factor to take in account. Thus, with data m/s SLOPE 3,5-4,5 30% Low 4,5-5,0 30-50% Higher 5,0-6,0 50-70% >6,0 80% Steepest 47 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 roofing is a work in progress, it does impossible to set a “perfect” system, which for the next years continues with the same performance that right now. European roofing materials have been pursued by the traditional technics till nowadays. It means that there has not had a previous study in each country to carry out them. That is not to say that there wasn't a previous idea about. The man has thought always in his comfort and the correct way to achieve it. If the research continues in a future maybe would be appropriate investigate in new materials which could have enough capacity to resist the change climate without the need of turn to regard the rest of the components. 48 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 REFERENCES (n.d.). A Green Affordable Housing. (2005). Roofing Materials for Flat Roofs. AEMET. (2015). Agencia Estatal Meterologia . Retrieved from http://www.aemet.es/es/eltiempo/observacion/ultimosdatos Allen, W., & Allen, B. (2014). Roofing in Europe. London. Apcarian, A., Walter, C., & Lassig, J. (2004). El efecto Wise en función del ángulo de la cubierta del edificio mayor. Neuquén, Buenos Aires. Bansal, N., Garg, S., & Kothari, S. (1992). Effect of Exterior Surface color on the Thermal Performance of Buildings. Building and Environment, 31-37. Bansal, N., Grag, S., & Kothari, S. (2004). 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Retrieved from http://en.wikipedia.org/wiki/Wladimir_K%C3%B6ppen 50 ARE THERE LINES WHICH CAN DRAW ON EUROPE A PROGRESSIVE CHANGE OF THE ROOFING PARAMETERS? HS-MAINZ – PILAR HUERTA NAVARRO - 913388 ATTACHED