sealing gaps with spray foam
okay, this question arose because I was researching the polyiso…. planning on using the frequently talked about method on this forum…. now, it came up to address any moisture problems in the house, particularly the basement, FIRST…… now, I guess I understand the reasons… the vapor from any basement leaks can make its way up thru the floor or into the walls all the way to the unfinished 2nd floor, whether its balloon framed or not….. mine being an old 1825 balloon framed home…. lots of changes to the home, and I have mostly block and some poured foundation… SO, on top of the foundation is the big beam(forget the name-rim joist maybe??) that the floor joists attach to… NOW there is a gap there that I tried stuffing a wire up thru and some what I think was fermiculite insulation came falling to the floor…… question IS, should I spray foam these gaps????? to prevent any moisture from heading straight up thru the wall… I wanna ask before I do it, the main house is 25 x 34… with another section 14 x 40…. picture a capital “T”….. so, thats alot of “great stuff” cans…. any help would be great……
final thought, maybe I should change my screen name to “The Winded One”
Replies
I'll bump you through again.
Wow thats a tough one--How big are the gaps? we talkin' and inch or two or 5?
Can't see why foaming the gaps close would hurt any--seems like the cavities are acting like chimneys moving heat up and out--
I could be missing something but if the gaps are of any size I would use foil faced foam board--doesn't have to be exact, just close and foam from there. Cheaper no dought.
Now that the crust has been broken I'm sure we'll hear from others---
just a hint---the Return key is free and unlike the paper we don't charge by the space---
Mike
"Even a blind squirrel finds a nut once in a while" Mitremike c. 1990
" I reject your reality and substitute my own"
Adam Savage---Mythbusters
I'm beginning to hate the Great Stuff as the nozels break, etc. Maybe time to invest in a foaming gun and seperate foam cans if you have to do alot of it. anyway...hard to see how moisture could make it up through vermiculate all the way to the second floor... if there's moisture in the second floor walls, might be another problem.... water leaking in trough poorly installed siding, poor soffit ventilation... how's the attic insulation look above that area...wet? good luck.
I think this was meant for you---
From: poetwithhammer 3:17 pm
To: Mitremike
I'm beginning to hate the Great Stuff as the nozels break, etc. Maybe time to invest in a foaming gun and seperate foam cans if you have to do alot of it. anyway...hard to see how moisture could make it up through vermiculate all the way to the second floor... if there's moisture in the second floor walls, might be another problem.... water leaking in trough poorly installed siding, poor soffit ventilation... how's the attic insulation look above that area...wet? good luck.
Mike"Even a blind squirrel finds a nut once in a while" Mitremike c. 1990" I reject your reality and substitute my own"
Adam Savage---Mythbusters
thanks for the fwd mike... I appreciate it.....
Todd
I have a foam gun now - it is SUCH a great tool! I wish I would have found out about it sooner, I got alot of gaps and mistakes to patch in this house. If your HD has the Hilti outlet, you can get the Hilti foam gun there... but don't get the Hilti foam. Instead, get the Great Stuff Pro foam. It's orange, and is code rated for fireblocking too! Makes your foam twice as usefull.
I use it where I would never break open a $5 can of foam.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
I picked up the Great Stuff gun, as it was only ~$35, and the Hilti was ~$80 at HD. I've burned through a lot of cans of EnerFoam and GS Pro trying to seal up our '49 house and a new addition.
We have a bonus room over the garage that leaks air like a sieve. Stud bays are open from the garage to the attic. The walls are paneling that isn't tight at all, and there are lots of other gaps.
For the open bays, I cut 1X blocks and strips of scrap plywood. Nailed the blocks into the studs, the plywood to the blocks, then foamed around the perimeter of each. So, for really big gaps, fill as much as you can with something cheap.
My only complaint about the gun is the straw tip for it. Just like a bigger version of the straws for the off-the-shelf cans at HD, just no threads or 45-degree bend. Easier to clean, but I've worn out one and I'm close to wearing out the other. And my vendor can't get me more of the tips (unless I'd like to buy 500 or so). Their suggestion- buy icemaker line that's close and use it. Haven't tried this yet, but it seems silly not to be able to replace the only consummable for this product.
http://www.efi.org sells syringes and needles for their Pageris foam gun. $0.75 a pop, daylight robbery, but what are you gonna do?
I would think you would want to fill those gaps with wood blocks. This makes for a firestop as well. You can foam or caulk around the edges. Waste of foam to fill large gaps that could be blocked instead.
Waste of foam. That made me smile! I find it hard to imagine wasting foam, rather than wasting wood for a non structural gap.Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Expanding foam costs more than wood, and is not as good as a fireblock.
I suppose it's not so much a "waste of foam" as it is a waste of the money spent on said foam.