Wiring new construction with spray foam

[Walkers]

I am about to break ground on a guest house that is roughly 750 square feet. 2x6x12 wall construction that will be spray foamed. Can Romex be run in the wall cavities then foamed in? Is this the best method? I’d hate to have to run conduit for everything, but if that is what is needed, then I supose that is what I will do. I vaguely recall reading that you weren’t supposed to run Romex in conduit because of the temperature rise in the conduit with the jacket on it, so I was suddenly worried that jacketed romex in foam insulation would have similar issues.

thanks,

 

[steves_001]

Run the wires as you normally would. Then have the foam done. Watch out if the area is a little loose between stud cavities as the foam will push them out some. When the foam is done they will scrape back to the studs and can damage the jacket/ wire.

 

[Jim greengo]

Just make sure you never have to add anything later.

 

[dcg9381]

Wire first, then spray foam right over it around here...

 

[Walkers]

Just make sure you never have to add anything later.

Yeah, which is why I was debating running conduit. Or maybe I just put a piece of conduit in every other wall cavity prior to foam.

 

[75gmck25]

Also make sure all the wall boxes are covered by the foam contractor, or that you do it yourself. I really like the foam for insulation value, but it goes everywhere when they are spraying.

 

[mike93lx]

Wire everything normally and you'll be fine, IMO. Adding a bunch of conduit is likely not going to help. Especially in just exterior walls

That said, think about stuff like tv placement and do add conduit for a/v wiring

Romex is completely fine in conduit.

 

[Max]

If you are going to do additional wiring - alarm, cameras, ethernet, audio, video etc. - make sure you get that in too. Spray foam will make it nasty to do that kind of stuff as rework…

 

[PT Doc]

Wire normally. Spray 2” on inside of sheathing. Blow in fiberglass for the remainder.