The Applied Building Technology Group has created a tool to help coordinate energy code thermal insulation compliance and building code water vapor control compliance for a proposed wood frame wall assembly on a commercial or residential building.
It performs the following two design checks for a user inputted wall assembly:
- Computes the assembly U-factor (and effective R-value) and compares it to code minimum thermal performance requirements (maximum U-factors) found in 2015 IECC Tables C402.1.4 and R402.1.4 (IRC Table N1102.1.4) which are climate dependent. An R-value of 0.17 and 0.68 are assumed for exterior and interior air films, respectively.
- Conducts a water vapor control check as an aid to help determine if the proposed wall assembly also complies with minimum building code requirements associated with various interior vapor retarder options which are dependent on climate and other factors such as insulation amount and location or sheathing type/permeance and cladding ventilation.
The user is encouraged to confirm the suitability of this tool for the intended application, verify all outputs and recommendations, and seek professional advice as determined necessary.