Strategies to avoid losing sustainability goals to budget considerations
World Trade, Boston, MA pursued SITES, LEED and WELL certifications using a durable yet traditional roof assembly.
Assembly used to demonstrate savings by using product specific EPDs. EPDs available at www.gaf.com/specadvisor.
Additionally, insulation can reduce the overall operational carbon of a building by reducing the overall heating and cooling loads. More insulation = less heating and cooling = less operating carbon. Studies have shown that if a building in Climate Zone 4A was built with an initial roof containing R-30 insulation, and the insulation was increased by R-10 every 20 years when the roof was replaced, the cumulative operational carbon savings would be 705 Metric Tons of CO2e, the equivalent of driving a gasoline powered car for 3.525 million miles [1]. This includes taking into account the embodied carbon, replacement embodied carbon, and end-of-life disposal. It is important to note that there is a limit to the ROI on adding additional insulation to a roof assembly. Finding the right balance for your project depends on a number of factors such as energy use, energy cost and CO2 emissions [2].
Decreasing operating and maintenance costs
Long-term building owners are concerned about operational and maintenance costs in addition to the initial cost of the building. This is also a sustainability goal, even if it is not always framed as such. One way to improve both operating and maintenance costs is by designing a durable roof assembly. One example is to bury fasteners for the roof assembly below at least one layer of insulation to reduce thermal bridging and increase the effective R-value. Installing a coverboard will protect the insulation from roof traffic and puncture, including hail damage and wind borne debris. Finally, selecting a robust roof membrane or even a hybrid roof assembly will reduce the frequency of future roof replacement costs, and the related accumulated carbon.