OK to spray foam by removing siding?
Well,I finally ordered spray polyurethane foam (TigerFoam) to use on the upstairs bedroom. I pulled the wood paneling off and exposed the framing (and the hornets, spiders, moths, and other wildlife). But I’ll have lots of foam left over after I finish that wall (it’s about 350 board feet and I ordered 600 bf) so I’m planning the next target. I’d like to do the downstairs bedroom wall, which is sheetrock on the interior. I plan to remove the siding and sheathing and existing fiberglass insulation (and whatever wildlife is inhabiting it). The siding is vertical cedar boards with felt over plywood sheathing (one story on that wall).
I think it will come off easily (waiting for a dry sunny day) but I wonder if it’s OK to apply from the exterior. Will the foam pop the drywall inside from expansion? Any other hazards I should consider?
Thanks in advance.
Replies
Finally hearing from someone that actually used
the "tiger foam". Do you have anymore comments on their product
as far as how the application went. I plan on using it when I finally
build my house and was wanting to know how hard it was to use.
And was the coverage as advertised? Cost for the 600BD package?
But in regards to your question about popping your sheetrock off
Me thinks that if the foam can expand to the outside than your
sheetrock should be safe, that is if your pulling all the exterior
siding and plywood of the studs. But I'm wondering if your
not making more work for your self and just do it from the inside
and pull the sheetrock off,foam and then re-rock.
edited to add: You could cut your sheetrock 12" from the
ceiling and 12" from the floor. That way your not having
to remove the base or crown. Also you won't have to finish
the ceiling to wall joint. All you'll have is butt joints on
the rock. Study up on the "EZ" mudding and it'll look like a
pro did it.
Even leaving the sheetrock
around the window trim and using 1x backing where it hangs
past the framing. I think this would be a whole lot EZier
than pulling off the ext. siding. But that is just me.
Edited 3/8/2006 7:34 am ET by butch
butch: Thanks for your suggestion about removing drywall. I haven't tried to pull the siding off yet (hoping it will quit raining/snowing before I am ready) so I"ll keep that in mind as an alternative.
I'll let you know how it goes when I use the foam. It's due early next week. Should be interesting.
Is that plywood sheathing there for shear resistance? Are you in earthquake or wind country? If so, it might be easier, cheaper, and safer to demo and replace the drywall.
-- J.S.
Is that plywood sheathing there for shear resistance? Pretty sure it is. But if it's just one wall, one story high, and I do it in one day and I screw it back the same day, is that very risky? I'd hate it if the house fell down...
you will have a mighty good time pulling nails spaced 3oc on the perimiter and 80c in the field... just pull down the sheetrock and save yourself a ton of work.
james
What the others said. Do the sheetrock. Another plus is you can do it even while it's rainy and cold, since you'll be inside. Wear a charcoal respirator, minimum. Fresh isocyanate is very toxic (remember Bhopal?) but only for a short time period.Bill
I agree with the others, inside work may be better. But that being said, my thoughts were like yours, remove outside siding and save the interior. Let us know how it goes because I was investigating the same product. I guess it depends on which skin you think you can make look better. Outside skin would definitely being less messy.
The danger isn't so much having the plywood off. Mostly it's the danger to you in trying to get it off with all the nails in it.
Then putting it back on the problem is that the edges, which are the most important part structurally, are chewed up from the old nails, as are the studs, and they'll all get another munching from putting the mess back together. No way can it go back together and be as strong as it was before -- well, maybe if you use PL premium adhesive you could make it strong enough.
In any case, you won't end up with what the engineer designed. Would you pay an engineer to figure out the strength of what you plan to do? BTW, screws are a no-no. They're brittle unless you get special ones, and inspectors will -- and ought to -- nix them.
Much easier and safer -- both doing it and for the long term structural issues -- to blow out the sheetrock and re-rock the inside.
-- J.S.
Thinking just the same as Tightwad, my 100 plus yr old has nice plaster walls, the ceiling heights are 13' down, and 12' upstairs. I am just guessing, but with those high ceilings, wouldn't there be some horizontal framing lurking in them there walls?? I don't see how I could get the texture right if I patched the holes I made in the plaster (and never hear the end of it!). Thinking icynene. The house has wood siding, some tar paper, then the lathe and plaster. ANY IDEAS? Thanks
Retired1 (boy I wish I were),
I peeled off some siding boards when I was looking at doing it that way (btw I didn't) and found that I'd have to pull up not only the deck which surrounds darn near the whole house but also the deck ledger boards since they are tied in through the plywood sheathing. THere's also metal flashing between the deck boards and the sheathing.
As it turned out, I didn't have enough foam to worry about that, it didn't go as far as I wished it would. Keeping the foam warm enough was the problem - the tanks cool down as you spray (Boyle's law) and even though I stopped to warm them before I was done with one wall, I didn't get as much as I should have.
I did find that it would be nearly impossible to spray effectively into a small enclosed area. The stuff doesn't flow, the spray heads need to be nearly perpendicular to the surface you're spraying (overhead just makes a mess), and it cures so fast (30 Sec) that it would just get in its own way if you tried to fill a wall from a small hole in the top or bottom. Soooo... it seems like you're right, if you can take the siding etc off and spray you can do one section at a time.
Tigerfoam is not the same as icy, it's a different foam formulation and may cure, etc differently. It does allow you to stop, rewarm the tanks, change spray heads and do another section in a day or two. So you don't have to peel off the whole house at once! I still think that doing it from the exterior is feasible.
Boy the whole house is warmer with that upstairs wall covered in foam. Less drafty, feels a lot warmer at the same temp, floor isn't as cold, etc. The stuff strengthens the walls also. And I'm really glad to eliminate those hornet nests, mouse nests, moths, flies, and other wildlife that were happily living in the fiberglass.
I hope you'll share your success with us once you start.
Best wishes