Please critique my wall design
Looking for opinions…
Climate zone 6
Wall design from interior out:
1) Sheetrock, 2) 1.5 inch service cavity for electrical using horizontal furring strips, 3) 1.5 inch foil faced polyiso that will be taped and sealed to be the vapor barrier, continuous insulation and air barrier (also radiant barrier with 1.5 inch air space from service cavity). Using scissor trusses so polyiso will extend up ceiling creating continuous envelope. 4) 2×4 stud wall with fiberglass batts, 5) fiberboard 1/2 inch sheathing (with supplemental metal diagonal bracing to protect against panel degradation over time) to provide a vapor open environment so wall can dry to the outside. Fiberboard also adds r1.3 to increase continuous insulation above the code requirement of r10. 6) textured WRB to also act as rainscreen 7) siding (not sure what).
1) Horizontal furring strips can be the point of connection for interior walls so no need to create a break in polyiso vapor and air barrier to attach them to exterior walls.
2) Service cavity keeps from having to puncture polyiso.
3) 1.5 inch horizontal air space creates near optimum environment for foil on polyiso to act as radiant barrier (equal to around additional r3 value)
4) Horizontal furring strips make cabinet installation east if placed in the right spot.
5) sheet rock screws don’t penetrate air and vapor barrier.
1) wiring more difficult and expensive (metal boxes and conduit)
Let’s hear what you think?
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