A Review of Roofing Methods: Construction Features, Heat Reduction, Payback Period and Climatic Responsiveness

Abstract

The roofs of buildings play an essential role in energy efficiency because a significant amount of solar radiation is absorbed by roofs in hot weather and a significant amount of heat is lost through roofs in cold weather. This paper is a systematic literature review about roofing methods for flat roofs. Ten roofing methods are reviewed in this paper. They are concrete roof, cool roof, insulated roof, roof garden, photovoltaic panels’ roof, biosolar roof, double-skin roof, roof ponds, skylight roof, and wind catcher. The review covers each roof’s main features, heat flux reductions, payback periods, and the appropriate climate for its implementation. Furthermore, the basic principles for selecting appropriate roofing methods are discussed and future studies for integrating these roofing methods are suggested. Some of these methods can eliminate the need of installing HVAC (Heating Ventilation and Air-conditioning) systems and others can achieve a high percentage of heat reduction if they are the right choice and they are implemented in the right circumstances. An incorrect selection could result in mild to severe energy penalties. The review contributes to the increasing knowledge about sustainable roofing and helps designers to increase building energy efficiency by selecting the appropriate roofing method.

Effects of Extensive Green Roofs on Energy Performance of School Buildings in Four North American Climates

“…Vegetated roofs mitigate the heat flux through the roof by shading the roof surface with plants, evapotranspiration of the plants, and the additional thermal insulation and mass, which are caused by the growing media [4]. There is a wide range of investigations that show the other advantages of green roofs such as reduction of stormwater runoff [5][6][7][8] as a Low Impact Development (LID) option, urban heat island effects [9][10][11], sound insulation [6,12], enhancement of the life span of a roof [13], creation habitats for species, and improving air quality by absorbing CO 2 and producing O 2 [14][15][16][17][18][19][20]. Due to the aforementioned benefits of green roofs, many local authorities in different countries have implemented the policy for using green roofs in new buildings.…”

Energy Savings on an Industrial Building in Different Climate Zones: Envelope Analysis and PV System Implementation

“…In the consulted literature, it was found that many envelope studies are related directly to energy savings in tertiary and residential buildings [14]; therefore, profound analysis for industrial buildings is still needed. A large number of studies are carried out for hot and warm climates [15]. Valuable studies like the case studies in Austria for refurbishment [16], in Slovakia for a quantification of the energy demand [17], and a nearly zero-energy buildings study for the steel sector in Germany [18]; point out the following: most of the reviewed literature consists on case studies and generalizations are still required [14], and that for cold climates, an increase of insulation thickness is not cost-effective [18].…”

Cool Roof Impact on Building Energy Need: The Role of Thermal Insulation with Varying Climate Conditions

“…In fact, almost half of buildings' energy is consumed for thermal performance purposes [3]. Therefore, high-performing building envelopes are needed to meet energy efficient buildings [4]. Taking this into consideration, cool roof technology is a widely acknowledged strategy for building thermal-energy performance improvement, by acting mainly on energy requirement for cooling [5,6] and urban heat island (UHI) phenomenon mitigation [7,8].…”