Foilface iso board on inside of SIP wall
Calling all vapor barrier experts!
I have a question about the suitability of putting a 1 inch layer of Thermax/Tuff-R/whatever manufacturer calls it, on the interior face of the SIP walls of the house I’m slowly completing.
I need to space the drywall inward to accomodate wiring that will be on the inside face of the SIP wall, so I figured I’d upgrade the R value with the spacer and kill two birds with one stone, adding a radiant layer and a vapor barrier. Cost of heating went way up since I started this project, so this upgrade seemed like a good idea.
Can anyone out there imagine any possible negative consequences to this setup? I know there’s debate about vapor barriers but this seems harmless. Would unfaced insulation make more sense?
Any help would be greatly appreciated.
Thanks,
Nick
Replies
Your SIP's don't have wiring chases???
Hi
No, I wanted the freedom to put wiring where I want it and to make changes in the future. Airspace was always the intent, additional insulation and foil face came later...
Nick
Do you have to deal with building codes where you are because some may not like the wiring on the surface. I know my building inspector asked about it when we first discussed SIP's with him. He wanted wiring set back like required in a stud wall. The chases enabled that.
Hi
I built a model of the method and got it blessed by electrical inspector. Romex will be covered by .060 x 1/2"d x 1-1/2 wide channel per NEC. I got a pile of this channel at an industrial salvage place. This method makes for a flexible placements.
Nick
PS
Inspector also said steel BX would be acceptable but that aluminum shield BX would not. Inspector used to build SIP houses.
Nick