Using foam in a can to fill gaps

I prefer a gob of silicone caulk.

use disposable gloves and keep it off your skin.

use some latex or nitrile gloves, this stuff is really sticky
wet your fingers in water and you can use your hands to tap it down if it expands to much

once it hardens..do NOT cut or trim the expanded foam
this is not closed cell, once the surface is cut this stuff will act like a sponge and absorb water, the smooth surface skin of the foam must remain intact
this is what makes it weather/water proof

I'd suggest to use the landscape foam. It is designed for exterior use and expands like the yellow urethane in a can. It also sticks to everything.

I have used the low expansion roam around my windows. I remove the inside frame, fill the gap all the way around, then put the frame back up...I have done this as I have found the seal used between the window and trailer are inadequate.

I have also used it to block the AC duct at the back of the trailer, as it doesn't terminate.

Cale

I used the expanding stuff (closed cell) in our TT to fill every gap and hole I could find through the floor. If you squirt in a small amount knowing it expands a lot, it's fine. You can always trim away excess with a utility knife. I had about a 10"x10" hole in the floor next to the furnace that I can to patch with plywood first, then expanding foam. The only hole I couldn't get to was under the shower base so I reached in with pieces of tuck tape as best I could.

Polyurethane expanding foam sticks like crazy to pretty much anything. Need to be extra cautious not to get any on vinyl flooring, cabinets, etc. Gloves are a good idea. If it gets on your skin, it takes days to get it off.

We had a lot of air leakage through the floor and sealing it all up has made a noticeable improvement.

In addition to what the others have posted, I will add that there is a special type of expanding foam called "pest block". This is supposed to taste bad to mice and other animals and keep them from chewing through it (they can chew through the regular stuff). I have bought pest block from home depot and have used it in our house. I don't know if it works or not, but so far no chewing through it and we have mice in our area.

Steve

DrewE wrote:
If you haven't worked with it before, be aware that it's rather messy stuff. It'll stick very well to your clothing, your skin, your cute little Scottie with the red bandanna around her neck....

Got a nice little chuckle out of that :)