I have a closet in the master bedroom of my home that is on an exterior wall. Unfortunately there's no insulation on the back wall of the closet and so a lot of heat escapes. We keep the closet door closed and that helps. The closet is about 6 feet wide and there's drywall on all walls of the closet.

I was thinking about using a spray foam to try to remedy this. I wanted to drill large holes at the top between each pair of studs and drop a little tube via which I could deliver the foam insulation.

My question is, what kind of personal protection equipment is necessary here? I have goggles for sure. I have a cheap mask. Should I use more heavy duty respiratory protection? Also, do I need a protective suit over my clothes? I've seen this on YouTube.

As the foam is curing, I saw a YouTube video that described the reaction as exothermic. Is there ever a fire hazard with deployment of a foam?

  • 1
    I'd suggest taking down the sheetrock and using foam boards if you want to use foam. In the end, likely less work than trying to spray foam behind it.
    – DA01
    Commented Nov 26, 2013 at 15:58

2 Answers 2


Cheap masks are for debris not chemical inhalants, you'll need a respirator. One-component Cans only require fan ventilation. *See page 15 of referenced link.

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If you not actually spraying it you might get by without a suit but due to some prep and finish work required, wear gloves.

Dependent on the laws in your county, but most require >15% flame retardants be put in and it shouldn't reach a combustible heat for anything except dust and maybe some feces.

If you are pouring it in, it takes more effort but is safer you can buy 2 part polyurethane foam mixes, it the same foam but with less additives. I actually can't use spray foam due to building code regulations but I can use the mix-and-pour kind.

Picture and tons of helpful information on spray foam can be found here: http://spraypolyurethane.org/Workbook


There is an expanding foam product made specially for injection into stud wall cavities. I don't think standard "spray foam" insulation is appropriate for injection into an enclosed cavity. Generally spray foam is applied to exposed surfaces. At any rate, in terms of the required personal protective equipment, you should be able to get a hold of a MSDS (material safety data sheet) for the product you are considering, either from the vendor or from the manufacturer. It will list the required personal protective equipment. This may vary from one type of foam to another.

For enclosed walls, you might consider blown-in cellulose insulation. This is a common choice for retrofit applications.

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