Foam board insulation

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Itslay90

Feeling the Heat
Dec 16, 2022
425
Upstate,NY
With foam board insulation. Can I put it on the concrete wall and just leave it like that, or should I just frame my basement plus drywall?
 
Consider as a start:
  1. Add 2 or more inches of closed-cell foam in direct contact with the walls and then frame normal stud walls including batt insulation and water-resistant drywall inside of that or,
  2. Glue foam only to the walls that has a fire-resistant layer facing the living space (e.g., R-Max IIRC)
 
Fyi. There are some paints available that you can put on foam to achieve the required fire/smoke rating. The bad news is they often contain lead in them and applying them requires proper ppe. Once it's dry the lead poses little risk.
 
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That one is actually water based and can be covered with latex if wanted. Rdr has a few options for barrier type paints.
 
That one for sure meets code and insurance requirements here in ontario Canada . It's Warnock hershey certified and has the ignition requirement testing as well. It does have the lead aspect unfortunately.
 
With insulation generally, you're always better off with an air gap.
 
An alternative to foam on an interior wall if its available in your area is Rockwool board. It is installed like foam but no need to cover it for fire rating as it will not burn. The bummer is in my area of NH and SW Maine I can find anywhere that stocks it.
 
With insulation generally, you're always better off with an air gap.
Not on a cold masonry wall in a basement where condensation can form and allow mold to grow.
 
Consider as a start:
  1. Add 2 or more inches of closed-cell foam in direct contact with the walls and then frame normal stud walls including batt insulation and water-resistant drywall inside of that or,
  2. Glue foam only to the walls that has a fire-resistant layer facing the living space (e.g., R-Max IIRC)
Actually "mold-resistant" drywall rather than "water resistant".
 
An alternative to foam on an interior wall if its available in your area is Rockwool board. It is installed like foam but no need to cover it for fire rating as it will not burn. The bummer is in my area of NH and SW Maine I can find anywhere that stocks it.
Last time I checked it was also really expensive compared to foam. But that was a few years ago so I have no idea what prices are now. It would have absolutely been my choice if the prices were anywhere near close
 
Last time I checked it was also really expensive compared to foam. But that was a few years ago so I have no idea what prices are now. It would have absolutely been my choice if the prices were anywhere near close
I can’t get it down here. And I agree it’s not cost competitive.

The solution is to glue foam board to wall. Then tap con 2x2 stud wall to block through the foam and hang drywall.
 
I can’t get it down here. And I agree it’s not cost competitive.

The solution is to glue foam board to wall. Then tap con 2x2 stud wall to block through the foam and hang drywall.
That's what I did. 2" foam with seams foamed then 2x2 strips
 
I can’t get it down here. And I agree it’s not cost competitive.

The solution is to glue foam board to wall. Then tap con 2x2 stud wall to block through the foam and hang drywall.
A few caveats with this approach -- uneven or not plumb walls will translate through the finished interior wall. Also, any wiring and plumbing may need to be protected against future picture hanging and such.
 
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A few caveats with this approach -- uneven or not plumb walls will translate through the finished interior wall. Also, any wiring and plumbing may need to be protected against future picture hanging and such.
Yes! I agree. Is it faster than framing up a free standing 2x4 wall yes. It might be a bit cheaper too. It’s the way I’m doing my walls. Skipping the fiberglass insulation. Adding screw plates to protect wires.
 
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