DIY Spray Foam

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848
Location
Scituate MA
Thread starter
Would like to spray foam the rim joyce of one side of house. I just jammed insulation as much / far as I could. Had a quote $1200...bit heavy for me but I understand, got to bring in the big truck, prep. So I saw the big Dow Great Stuff Pro with the gun, fairly big cans. Here is one on Amazon. Anyone have much experience/recommendations?
 

JC1

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4,499
Location
Oshawa, Ontario Canada
When I finished my basement I sprayed the end of the joists with the regular cans of red dow spray foam.tbe big stuff. Just go slow and steady and let it stick to the wood a bit at the bottom before you go full blast. Are you trying to seal drafts? You could use those guns of you want, bit the regular cans work too. Did you estimate how many cans you'll need? Buy extra you can return the unused cans once you are done.
 
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926
Location
Virginia
I wouldn't use those cans to do this job. It will be tedious. But, lots of people use the cans in conjunction with rigid foam board insulation. There's a bunch of videos on YouTube that show the basic method.
 
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6,838
Location
MIchigan
Originally Posted by coopns
I just jammed insulation as much / far as I could.
FYI....You shouldn't Jam or Pack insulation because the wood won't get proper ventilation. Check one of the Home Improvement stores to see if they loan out Spray Foam Equipment.
 
Messages
3,651
Location
Worst Case, Ontario
What you need is something like this: https://www.homedepot.ca/product/to...ent-spray-foam-insulation-kit/1000718744 Those guns with replaceable cans are more for contractors who install a lot of windows and doors, I believe you can seal and reuse them as long as the can is not removed. The aerosol can is a single use item. You need more volume and expansion to seal a rim joist cavity. You can also apply fibreglass insulation and vapor barrier like a normal stud wall if you want to. It's one of the messiest tasks I have ever done.
 
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Messages
24,606
Location
Upstate NY
I would cut pieces of foam for the rim joist. And seal with caulk. The twin tanks of spray need to be sprayed at a certain temperature and there are some issues about how long you can wait after stopping spraying and start spraying again. You may need to change tips or something if there is significant time between stopping and starting up. Check on that before starting.
 
Messages
971
Location
USA
I've used the Dow Froth Pak. Two small tanks mixed at the nozzle. $300 I think to do the rim joists in my previous, little rambler. Excellent results, but you need to seriously prepare. Everything exposed and ready to go, critical surfaces covered, Tyvek suit, eye protection, etc.
 
Messages
4,148
Location
South Carolina
Originally Posted by Donald
I would cut pieces of foam for the rim joist. And seal with caulk. ..
Agree ^^^ its a valid method over just using plain spray foam. Get nice thick foam board, put it up and seal with spray foam. Much more simple for the DIY and many professionals will also use the same method. Me personally would spray some foam along any seams, place the foam board in right away and seal again with the spray foam.. Here is an example ______
 
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