How Much R-Value Do You Need?

It can be confusing to keep track of your climate zone code requirements due to the fact that the minimum insulation requirements have increased 66 – 100% over the last 9 years. It is important to remember that a building owner only gets one chance to increase the insulation in the roof system approximately every 20 years. When determining the desired R-Value, you should consider future energy requirements and associated energy costs over the entire lifespan of the installed roof system. The current codes reflect the MINIMUM requirements, we recommend when planning for the future to exceed the code by an additional R-10. (Paybacks typically can be seen in 6 – 10 years*)

This guide provides assistance when designing the minimum R-Value in commercial buildings for energy efficiency for thermal insulation above the deck. The respective R-Values are based on the climate for each stated region and only a suggestion. State codes may differ and should be considered. Current code information for each state is available on the websites for the Building Codes Assistance Project and the US Department of Energy Building Energy Codes Program.

Building Codes Assistance Project: http://bcapcodes.org/code-status/state/
US DOE: https://www.energycodes.gov/status-state-energy-code-adoption

The chart below shows the progression of the R-Value changes by climate zones since ASHRAE 90.1 2004.