Closed cell foam sprayed directly on block basement walls?
wiremanjon
| Posted in Energy, Heating & Insulation on
I’m meeting with an insulation contractor next week for a basement job in NJ. The salesman states that he would like to spray 1″ of closed cell foam on the walls and rim joists. The basement has no water leaking in and is dry, but does have some efflourescence “salts” bleeding through the bottom courses. Do you think this will be a nice dry, warm result? Is 1″ thick enough?
I would like to use pressure treated 2×4’s for the bottom plate and regular 2×4 lumber upwards of that. I will then construct traditional 2×4 walls spaced 2″ off the foam. I plan on using Moldtough green board sheetrock( I know paperless drywall would be better, but don’t see the need here) and no vapor barrier or further insulation. Any one think this is a bad plan
Replies
No one here has any experience with this?
I want my customer , who's also my friend, to be pleased with the results. There was an article a while back in Fine Homebuilding that says this is the best way to go.
Why not put the walls up, then have the foam sprayed in? Seems easier, and you could preserve some floor space. No fooling around with fiberglass either.
Just a bump & food for thought
No real experience to answer your questions, but if you look at the publications on insulating a house, they really seem to like spraying the foam over the basement walls, mudsill, & rim joist areas. Besides the insulation value, it helps eliminate a lot of potential sources of air infiltration.
On the efflorescence, it's possible some of that may be left over from construction before everything was dried in, waterproofed, and backfilled. Happened in my house. Had a really wet period with just the basement walls up. Regardless, checking for moisture seepage in the walls before spraying, would be added insurance, IMO.
Just duct tape a piece of poly, saran wrap or aluminum foil to the lower part of the wall. Seal the edges well. Leave it a few days, the peel it off. If there's any moisture on the underside of the poly, there is moisture coming thru the walls. If that's the case, that should be addressed before you do anything else.
Not happening
Turns out the foam needs two days with everyone-including animals out of the house. I'm going to plan 2: Paint the walls with water proofing paint, then adhering 1"or 2" XPS foam boards to the walls. The sill plate details will be time consuming, as will the fireblocking at the top of the foam.