My house inspection noted that the exposed blue foam insulation in my basement is not to code and (if there’s a fire) could be dangerous due to noxious fumes. The insurance provider has told me to remove it, or cover it with drywall to ensure ongoing coverage. I am trying to decide which path to take, without spending a large amount of money.

Options (as I see them):

  • Remove it
  • Cover with drywall (without framing) and using concrete news/screws
  • Vapor barrier, frame it, cover it with drywall (probably not actually an option because I can’t afford it with current lumber prices)
  • Something else?

More Context: I’m in Atlantic Canada (winters are long and cold). The house is old (1928), and already not very efficient. The basement is not usually wet, but there can be some pooling/dampness when the snow thaws in spring. With this in mind, I’m worried that covering the blue foam with drywall might present a mold issue unless I invest much more money in the solution.

Question: Am I crazy to remove the foam entirely? Will I be affecting efficiency a ton by doing this? (this is my favorite option)

Additional context:

  • The foam does not cover all walls. Probably about 2/3 of the basement wall surface is covered.
  • I have no plans to ever finish the basement
  • I can’t afford to fully waterproof my foundation at this time (we have a sump pump, and that will have to do for now)

Covered section of wall (see damp staining)

Uncovered section of wall

  • 2
    First I would verify that the foam is a problem contact the MFG, I can’t even count the number of times a home inspection has made claims that are not fact!
    – Ed Beal
    Commented Jul 13, 2021 at 13:47
  • 1
    4/6? Looks more like 8/12 to me. :P
    – isherwood
    Commented Jul 13, 2021 at 14:28
  • 1
    I would probably remove it to appease the insurance company, then, when lumber prices aren't stupid, build energy walls throughout and reuse (or sell) the foam. That's assuming I was planning to stay a while, and assuming various other things about my life.
    – isherwood
    Commented Jul 13, 2021 at 14:36
  • 2
    What's on the other side of the foundation wall? Is it dirt or is the majority of that wall exposed to the open air? If the former then you might not notice much of a difference by removing it. If the latter then your basement will most certainly feel colder.
    – MonkeyZeus
    Commented Jul 13, 2021 at 14:42
  • 1
    While you're at it, consider getting some sort of insulation in between those floor joists in the ceiling of that cellar. It'll pay for itself in a couple of years, and the room above will warm up quicker, and feel more comfortable.
    – Tim
    Commented Jul 13, 2021 at 15:40

2 Answers 2


Get that blue stuff out of there, it will burn very aggressively and turns your house into a firetrap. Houses are actually more flammable these days and stuff like that is why.

Petroleum based foam can even make a hard rock mine burn, generally thought impossible. In that incident, it was not only a powerful accelerant, it emitted toxic smoke which incapacitated people.

It's why the latest advice is to sleep with your bedroom door closed.

If you want to put up other kinds of insulation when the insane building market calms down... that's fine.

Note that the pinch point on lumber is the milling not the harvesting. if you have the means to mill logs into boards, lumber is cheap.

  • 1
    I have decided to go with this answer because -- safety first. -- However, I have also decided to re-visit suggestions from this answer as a way to get back some of that efficiency, without risking being overcome by toxic smoke if there were to be a fire.
    – user138192
    Commented Jul 15, 2021 at 17:41

The Styrofoam product and the products like it will be part of a class-action lawsuit in 20 years (like asbestos) because of how quickly it burns and the toxic fumes.

Also a note on your basement. This thin of insulation is not really doing anything other than acting as a solid barrier. Framing/drywall would do the same thing. If you are in a freeze zone in Canada you should have something much thicker there.

The other thing is your joist caps. I see that crappy thin insulation and then right above it nothing. This is the area that you have to insulate the most. If you insulate joist caps (where I see insulation on the one wall) and basically take Roxul about 1 foot out and 6" down... that provides a very tight air barrier to the outside and is the most effective way to keep a basement conditioned. R-value doesn't mean crap when cold air is getting in. Having more r-value and covering the caps is 90% of insulating a basement. The concrete itself is already doing that on the walls - yes you can add to the concrete but priority should be the top.

And based on your comments about the other side of the walls being mostly dirt with maybe a foot at the top exposed... all the more reason to be more concerned with insulating the cap area better. In the midwest we only insulate about 1' below grade So you would insulate the top 2' of your wall as there are no returns past that. Being colder climate though this top 2' is still most important but you should have r-10ish at least for the rest just for energy efficiency.

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