Double stud wall to ICF frost wall – GreenBuildingAdvisor

LowSlopeRoof | Apr 16, 2026 07:33pm | #2

On the outside of the outer wall is 5/8″ sheathing, 1×3 strapping for a rain-screen gap, and the siding. The structural engineer allows half the height of the bottom plate(s) to overhang the concrete core of the ICF, meaning 1-1/2″ maximum. This leaves 4″ of the structural 2×6 over the core, then a 3″ gap in the 12″ double-stud wall (all over the core), but only 1″ of the core left to support the inner non-load bearing 2×4 wall. I’m not sure that should be an issue since its’ not load-bearing. It would be sitting on 1-1/2″ of subfloor which sits on 4″ of EPS insulation, which sits on 4″ of concrete slab. Sounds OK to me…