Sustainable Roof Deck Construction Since building designers should look forward 10, 20, even 50 years into the future to evaluate the environmental impact of a building, the design team would like to ask for a credit interpretation concerning the use of aggregate lightweight insulation concrete as the roof deck construction to minimize future material waste created during expected reroofing activity. Depending on the type of roof system, quality of application, and environmental factors, the roof system on a building with an estimated life expectancy of 50 years could be replaced two times or more. Material waste occurs as the roofing system and insulation are removed and unfortunately sent to a landfill for disposal. Board insulation material is currently not a recyclable waste stream. Aggregate lightweight insulation concrete roof decks are generally reroofable, and therefore eliminate board insulation disposal. Further, the mass effect of thermal inertia increases the life expectancy of roof membrane systems. These are the environmental advantages of aggregate lightweight insulation concrete. Intent: The design team proposes to reduce the amount of material waste created during a reroofing activity by 100% and increase the life expectancy of the roof membrane by using an aggregate lightweight insulation concrete deck. By using an aggregate lightweight insulation concrete deck, the environmental impact of new insulation manufacturing is also eliminated. Requirement: The building design would incorporate the use of aggregate lightweight insulation concrete as the roof deck instead of an insulation board-based roof deck. During a reroofing activity, the aggregate lightweight insulation concrete deck would be inspected, repaired if necessary, and re-used as a substrate for the next roofing system. Submittals: Data sheets on aggregate lightweight insulation concrete and insulation board. Calculations comparing the amount of material waste created by each system. Life cycle cost analysis comparing both systems. Thermal inertia data. Design Approach The aggregate lightweight insulation concrete would be poured-in-place to create a monolithic deck. This deck would provide a suitable surface to receive the new roof system.
While the strategy of designing a lightweight insulated concrete roof deck that increases the roofing membrane\'s life expectancy and reduces material wasted in the process of re-roofing is commendable, the strategy by itself does not warrant an innovation credit. The adoption of such a roofing system alone does not demonstrate a comprehensive approach to systems selection for the entire building. There is no mention how the evaluation process was informed based on the total environmental benefits. There is also no reference of how this roofing structure affected the rest of the building\'s design, material selection and quantity of use, or what decision-making strategy was adopted for other materials and systems. Applicable internationally.