It’s $545 for 36 cans on Amazon.

I need to insulate and air seal my basement ceiling and rim joist bays.

I'ved used fire rated spray foam, but not that kind. Its a messy task and I would prefer the kind that doesn't require cleaning the nozzle gun. If you don't clean it propperly I imagine it will become an expensive nightmare.

Don't believe the coverage claims, it's always much lower.

https://youtu.be/2DuwMoezQLA

Also, Rockwool is a brand name of the generic mineral wool. There are other, cheaper brands of mineral wool, than rock wool and they work just as well.

First of all why do you need it

Second of all don't buy fire barrier products from Amazon, your local hardware store or electrical supplier will have correctly rated and fresh product.

If you are doing this work as a contractor, get any building inspector you've met to tell you about the products they approve for this.

that was a good video, and the followup one too

those guys have good video presense. I will keep them in mind next time I need a video like this. Thanks!

As said previously, purchase locally. And also don't consider spraying this into the tailpipe of an ICE (Internal Combustion Engine) vehicle.

Yes, 10 years ago when I bought the house and brought the internet cable inside. No problem, never had to change it. No idea what brand it was.

Great video! I need to do a basement ceiling and rim joist bays and the budget is tight. If you know where I can order the other brands of mineral wool, I would love to know too.

I need to insulate my basement ceiling and rim joist bays on a short budget.

That's really interesting to me that they use "board feet" for the coverage. For lumber, board foot is a very specific measurement that means a square foot, one inch thick (so 144 cubic inches). The insulation value is then measured at 2" thick. Unless DIY spray foam means something different by a board foot then coverage is going to half the area at the advertised R value, and roughly a third if you fill in the 2x4 framing cavity.

Professional spray foam is pretty expensive, but it's probably a way better idea than than this DIY stuff. The mineral wool is probably fine, and I would happily let somebody punch me in the stomach if it meant I didn't have to mess with fiberglass batts.

I have done the rim joists in my basement using a similar spray foam product. The biggest recommendations I have are:

1. Use the kind of gun pictured and not the cans that come with a straw. It is much easier to apply consistently and you can actually stop work and start again the next day using the same can. The straws work OK but they always get clogged when you stop for a bit so only use them if you are working on a small area and plan on using the whole can in one go.

2. Look into the difference between closed cell and open cell foam. I've never seen closed cell come in a can like that so I'd bet money that is open cell foam. It works great for air sealing but you need to apply a ton of it to get an appreciable R-value. Closed cell foam is a lot more expensive in the spray form and is a 2 part mixture that is more complicated to work with.

What I ended up doing was buying some 2" closed cell foam board at the local hardware store. It's relatively cheap in board form and is easy to cut. I cut a piece of the foam board to fit inside the rim joist space and then used the spray foam to air seal both the rim joists themselves and the small gap around the foam board. I think this is the most effective way to do it unless you go for the 2 part closed cell spray foam but that was more than triple the cost of the foam board + open cell spray foam.

For comparison, the 2" foam board has an R-value around 8 and, if memory serves, you would need something like 8" of open cell foam to provide that same level of insulation. You can get an equivalent R-value with 2" of the closed cell spray foam but last I checked the spray stuff was about $800 and an 8'x4' sheet of 2" foam board is around $60.

I don't recommend spray foam for a number of reasons, a few being that it offgasses VOCs after installation and can obscure or make future access to repairing surfaces impossible. If, for instance, water in your bathroom seeps into your subfloor, that repair becomes suddenly infinitely more complex if you have to fight through spray foam.

I highly recommend mineral wool batts, even if you do thin ones. They can be cut with a thrift store bread knife/any serrated knife and friction fit between the joists. Very easy install for an amateur, very forgiving. Save the spray foam for those tricky gaps next to doors and windows.

We bought ours from a local contractor supply store, and it was cheaper than Orange or Blue store and they delivered
for free. Not sure where you're at but search around.

Oh this will not fill as much volume as you need. This is for plugging holes into a garage or through some other fire rated wall.

Rockwool insulation held up with string, and then poly sheeting stapled over that is probably the cheapest way to do it correctly with a high R value... Idk though I'm back to asking an inspector what they would accept, but I work construction so I speak to them. Your hardware store randos will point you in a better direction than me probably.

Yeah the spray foam is not the answer for large areas. It's for touch up after the fact. You may want a can of it at the end.

Use a wool insulation like this dude said

This is the correct answer. Or use old school pink insulation.

One newer alternative my contractor used is timber hp, its physically like a block of firm tofu so you take the chunk/board and muscle it into the joists and it just stays. Its cool but cutting it looked miserable.