How to Challenge a Building Code Interpretation – GreenBuildingAdvisor

Code Green

Code language, building science, and ICC interpretations can help resolve disagreements over how a building-code provision should be applied

A builder in New England recently commented on a Green Building advisor post with an interesting code question:

“On a residential project the building official stated we must install fire blocking on the exterior rain screen at the bottom, between floors, and top between the furring strips. My take on section R302.11 is that it is intended for construction at the interior side of the wall sheathing but there is ambiguity that could lead to applying it to exterior furring.  Adding blocking in a vented rain screen essentially defeats the effectiveness of bulk water management and drying. Has anyone has run into this issue with a code official and if so, what was the outcome?”

The post generated a flurry of conversation because the interpretation appears to conflict with both the building science behind the use of a rainscreen and the intent of the fire blocking provisions.

I’ll come back to the rainscreen question, but the question raises a broader issue: What do you do when you disagree with a building official? The answer shouldn’t begin with an argument. It should begin with the code.

Start with Chapter 1

I have written before that Chapter 1 of the IRC and IECC are often heavily amended during the adoption process. Nonetheless it is the place where we need to start when there is disagreement about how the code should be applied.

Both the IRC and IECC contain administrative provisions addressing applicability, conflicts, and the authority of the building official. One important concept is that where different sections of the code impose different requirements, the more restrictive requirement generally governs.

To explain this, I often point to the IECC Requirement in Section R403.3.2 Building cavities, that section states that building framing cavities cannot be used as ductwork or plenums. I talked about…