Long story short, find myself in midst of a remodeling project in which it has been decided the former cellulose insulation that was in this 4' x 8' wall cavity is to be replaced with sprayed foam.



Called an insulation company and after he finished laughing out loud, realized I was serious. So he suggested I go to a box store and get a "frost pack" spray foam insulation kit and do it myself.

For those that know, is this something that is safe and doable by mere mortals?

I don’t know much about it, but did he laugh because it was such a small job?

oh yeah spray foam is super easy you can also buy spray foam in a can and it works just like spray paint that might be a lil easier.
pro tip when working with spray foam wear a shirt you don't care about.

I would but 3 1/2" iso board cot to fit in the cavitys
A small amount of great stuff up one stud where it meets the plywood and across the top down the other stud and across the bottom plate and install the iso board

Spray foam has a tendency to fall out of vertical spaces
That's why he laughed

Don't ask how I know

Wetdog, no he laughed because they just can't do a job that size and make it anywhere near economical. Most spray foam companies would have a minimum job size way past what this project requires.

Spray foam, properly done absolutely will stay on a vertical surface.

But in this situation I would do it with the iso board just like wetdog suggested. It works and it works well.

I agree foam board and a few cans of great stuff spray foam will do that for much less cost and do it well

for 4x8 like that 2 sheets of 1 1/2 your into it for around 80 dollars in foam board and 2-3 cans of great stuff at about 7 dollars a can so just over 100 dollars

a froth pack is almost 400

would be cheaper and easier to get polyiso foam board and cut it a bit small to fill the spaces and then use a can of spray foam to seal the gaps.
cut the foam a half inch narrower than each space and a quarter shorter, this leaves room for using the can of spray foam to seal it well. you can layer the board , just make sure it stays in the wall when you spray the gaps. 3 or 4 1x2 fastened across the studs makes sure the spray does not dislodge the board outside the wall.
I have found that trying to fit the board tight never seals like it should as nothing is as strait as we think, hence the gap and fill method.

Yes......small dinky job.

That I can do......with almost zero waste. And having finished thickness of 3" vs 3 1/2 is good as it has that metal brace running thru the cavity. 3 1/2 " would never fit flush.

Professionals use higher pressure than a spray can
That was my point

I have used “froth packs” a lot. Usually about 500$ for a good amount of foam. I sprayed my rim joist in the crawl and basement before remodeling. Gives a lot of Rs and seals pretty well to prevent air movement. It is easy to do. Its a little messy but a drop cloth will be good enough.

like Trapr pointed out sometimes a gap is easier to work with and fill with the spray foam at the end while it is held in place the great stuff does well with 1/4 to half inch gaps.

FWIWTY: I helped a buddy build a shed he wanted insulated, so instead of buying fiberglass or ?, I suggested we just fill the voids with corrugated cardboard, worked out great and was essentially free. Heavily applied Borax crystals to any kill bugs.

Looks like you have a moisture or ventilation problem also in the shower
If you are doing tile,,,,, red guard is your friend

And replace the control valve before you start

We went with foil covered foam boards way cheaper here then spray foam on my 32x28 shop.

What’s the fire rating on that foam how toxic can it be?

Yes, I noticed that too. The cellulose we pulled out of there did not have a vapor barrier. It was a glass walk in shower. Painted drywall above the shower was going south, allowing moisture into wall cavity.

Part of idea for foam was the vapor barrier part of it. Then Hardy board instead of drywall and floor to ceiling tile over that.

Red guard?????

A froth pack is about 400.00$.
Easy to do.
You will not need the whole kit for that small of area but could perhaps use it somewhere else?

I’m with DT. I just bought a “Froth” pack 200 from Menards to seal bottom board in our Ontario building project. I also did a lean to off my shop here in Nebraska with a froth pack 600. The 200 should be plenty for a 4’x8’ area, it cost $380 at Menards here if I remember right.

Another Froth pack fan here. Easy to use, seals up great, good value.