Sustainable Commercial Roof Design

Initiatives and Challenges: Building practitioners are constantly trying to develop more energy efficient buildings while maintaining and/or improving the human comfort. There are initiatives and challenges that have been set by both private and public sectors such as Architecture 2030 Challenge (Mazria, 2012) and 2025 Commercial Buildings Initiative (US DOE, 2008). The US Department of Energy (DOE) has come up with the Net-Zero Commercial Building Initiative (CBI), which strives to develop Net-Zero Energy Buildings (NZEBs) for commercial buildings by the year 2025. A NZEB is a building which can generate an equivalent amount of energy as it consumes in a year period. The CBI was launched in the year 2008 and DOE is collaborating with National Laboratory Collaborative on Building Technologies (NLCBT), architectural and engineering companies, and building owners to meet the goals of the project. While USDOE’s 2025 NZEB Initiative is driven by a public sector, the Architecture 2030 Challenge is from a private sector initiated by Edward Mazria and his organization known as Architecture 2030. Its target is Carbon-Neutral buildings by 2030.

Roof and Its Significance: To achieve either carbon-neutral buildings by 2030 or NZEBs by 2025, two major activities are outstanding, which are Energy Efficiency and Renewable Energy. Currently, for example, existing commercial buildings’ Energy Use Intensities (EUIs) are about 90 kBtu/sqft-yr (CBECS, 2008). This EUI level should be reduced down to a level of 30-40 kBtu/sqft-yr through the implementation of Energy Efficiency Measures (EEMs). This optimized energy consumption level will then need to be met not by fossil fuel sources but by renewable energy sources to achieve NZEBs. In this regard, the roof area has a significant role and great potential to be utilized for both energy savings (Energy Efficiency) and energy generation (Renewable Energy). Energy savings could be realized by innovative daylighting roof design, which potentially results in electric lighting energy consumption reductions. Also, renewable energy generation, such as through solar PV installation, is a very typical implementation on the roof area. Therefore, there is no question on the importance of better utilizing roof in buildings. Currently, however, the roof design is not an integrated effort between architects, engineers, contractors, and consultants. Most architects consider and design roof with less attention as merely as a space for HVAC or as mostly as a green roof. Most engineers are not active players but contractors in this regard that just follow the design. Now, there is a clear need for roof to be maximized and optimized for the development of sustainable buildings. Therefore, this research aims to develop the strategies and a tool for optimizing roof functionality in commercial buildings.

Goals and Objectives: The goals of this research are 1) to make aware of the importance of maximizing and optimizing the use of roof in commercial buildings and 2) to offer a new paradigm for building practitioners to be able to systematically approach, design and develop roof as a key platform to achieve NZEBs by 2025 and carbon-neutral buildings by 2030.