PIMA’s State Energy Code Fact Sheets provide a state-by-state detail of the minimum insulation requirements for low-slope commercial roofing in both new and existing buildings. Each fact sheet includes state-specific insulation requirements, code-compliant assembly examples, and links to helpful resources. PIMA monitors state codes regularly to provide the most up to date information possible.
The Washington State Energy Code, Third Edition reviews the energy-efficiency requirements for commercial building roofs in Washington. The minimum requirement for insulation installed entirely above the roof deck is R-38 for all climate zones. This code became effective on July 1, 2019.
Sample roof assembly diagrams and additional information can be found in PIMA’s Washington code fact sheet.