spray foam insulation, best to use for an old house?

[blue83ranger]

my uncle wanted me to do some research on what the best spray foam insulation would be, so if anyone has any thoughts on the stuff i would like to here it. It's going into a house that was built more than a hundered years ago. Inside, the exterior walls (brick) are now studed with 2x4's. We know some of the basic stuff about it like you use a different kind around windows and doors. and one guy locally said on this old house they don't apply it correctly. On the show they fill up everything then cut off all that sticks out, this guy says you don't want to cut it at all. He looked at a shed we would also like to do this to and he said we would only need about 2 inches and if it would be raining outside you wouldn't here a thing. (in a tin shed). So if anyone can point me in the right direction please let me know. and thanks in advance.

 

[skippy]

Hope this helps.Don't know why you were told not to cut it off,thats what the home improvement shows do.

http://www.icynene.com/

 

[baadboy11]

They always cut it off...unless its in the attic or something how else can you drywall over it?

 

[Shran]

I see no reason not to cut it off. Especially if you're putting trim over it, you'd want to cut it off so the trim fits.

Also keep in mind that removing it sucks, so don't let it dry on anything you care about.

 

[Sunk]

I've used Great Stuff and that works well. Keep in mind though, that it is EXPANDING foam, and that yes it is ridiculously difficult to remove from stuff once it's dried so watch you're doing.

 

[blue83ranger]

the guy told us that you don't want the end of it open. That they should of sprayed less so it wouldn't foam up past the studs. it allows air to get through it when they cut it, or so that guy says.

 

[srteach]

Expanding foam is a closed cell product. There are little bubbles of gas throughout the material. If you cut the skin off of properly cured foam, you only lose the insulating properties of what was cut off and any gas pockets directly opened by the blade. Use a sharp knife on cured foam and you only lose 1/16 inch of insulation more than what is removed. This is more than made up for by the fact that the foam expands to fill every crack and void, and will stop drafts. Because it is expanding foam, you must provide ventilation for the escaping gas as it cures. Most expanding foam is moisture cure, so follow the directions on the can for best results.

I actually used the expanding foam to securely pack 2 4.0L Ford engine heads for transport.

I also used the stuff to replace a bad basement window. Built a frame in the window opening, put plywood up, filled the middle with expanding foam. No air leaks ofter 10 years now.

 

[Captain Ledd]

Ok, let's try posting this a THIRD time without my browser going stupid and reloading 10,000 pages...

Srteach is absolutely correct. the nature of the foam seals it against all the surfaces like the outside wall, and the studs, and also any other odd area, crevice, or crack. Cutting off the front won't hurt it at all.

One thing to check on though is that while this stuff is expanding, I'm told it can reach 250-300°F (though for not very long), and can on occasion damage things like cable wires and phone wires. The electrical wires should be able to withstand it.

I've heard nothing but good about the stuff, I'd go with a different installer though.

There is open cell though, cheaper, much less R value per inch, and can allow water to be absorbed into it. Closed cell is the better product.

 

[triumphrider-1]

Pretty much what srteach and Captain Ledd have said, you have to shave it unless it in the attic or subfloor.

Personally, I would go with blown in cellulose (sp?) insulation. We've had it in three of our houses now (along with our pole barns) and put it into my grandfathers house and it has worked great.

I was told by a co-worker a couple years ago that his spray-in foam throughout his house was starting to loose its R factor. The foam will become brittle over time and start to crumble, ending up in a pile of dust in the bottom of the cavity (apparently the vibrations of doors closing, assuming hard, accelrates it ).

 

[Captain Ledd]

I was told by a co-worker a couple years ago that his spray-in foam throughout his house was starting to loose its R factor. The foam will become brittle over time and start to crumble, ending up in a pile of dust in the bottom of the cavity (apparently the vibrations of doors closing, assuming hard, accelrates it ).

Thats usually caused by possibly 2 things: UV light getting there somehow, and it's sub par foam. Back in the day they used this kind of nasty Urea (yes, like the urine) and Formaldehyde (nasty chemical that keeps dead stuff from rotting) based foam. it really is a horrible substance and is known to start breaking down. I think it can actually shrink too.

The foams now days are Urethane based, like polyurethane. Not nearly as icky and much more stable. They can actually use the urethane stuff for roofs, as in the exterior part that gets weathered on.

 

[triumphrider-1]

Thats usually caused by possibly 2 things: UV light getting there somehow, and it's sub par foam. Back in the day they used this kind of nasty Urea (yes, like the urine) and Formaldehyde (nasty chemical that keeps dead stuff from rotting) based foam. it really is a horrible substance and is known to start breaking down. I think it can actually shrink too.

The foams now days are Urethane based, like polyurethane. Not nearly as icky and much more stable. They can actually use the urethane stuff for roofs, as in the exterior part that gets weathered on.

Yeah could have been the old type (don't remember when he said he remodeled).

 

[Shran]

Another good use for expanding foam is body filler... clean the rotted part out so there's a clean hole, spray, trim, and cover with bondo. Obviously not the best solution, but if you've got an old beater that's full of holes it works great to keep the weather out.

 

[slimchriz]

Cellulose settles does not seal out moisture and can actually store it....

You guys are talking bout different things icynene is not great stuff close though.
the pros come in and spray it in the walls it expands a little past the studs and they shave off the excess it doesnt expand as much as great stuff.
to confuse things more great stuff has a windows and doors formula that doesnt expand as much its just to seal the narrow gaps. If you use the regular great stuff it could expand to much and distort the window or door frame making it hard to open/close... though Ive never seen it do so.

But if the house in question is old I dont know how you could do foam insulation in the walls

 

[Captain Ledd]

It sounded like he has added stuff on top of the brick, or has opened the walls back up and plans to just put drywall back over it.

I knew he wasn't talking about Great Stuff, I just ignored those comments. Holy shit that'd be alot of cans to fill a houses walls with.

I also live in a 100 year old house (well 96 - 1914) and our walls are hollow, I know this because of all the holes I've cut into them from redoing all of the electrical. So I've really been reading up on how to retrofit our house with insulation.

There is pre-expanded foam, which is a urethane based closed cell foam that doesn't expand as much and/or as quickly as the spray gun stuff. It's made to be poured into existing wall cavities through a hole and not push out the drywall (I'll assume plaster as well, ours is in surprisingly good shape I'd prefer to keep it for the time being) and has the similar R-value as the sprayed in stuff.

http://www.tigerfoam.com/products.php

They offer 2 formulas. The fast rise one made for use with the gun and a slow rise one that fills much the same as a blown in type insulation, from a hole drilled at the top of the cavity, minimal invasiveness. Both products super sealing out the elements much the same.

 

[Ranger Dave (B25)]

Another good use for expanding foam is body filler... clean the rotted part out so there's a clean hole, spray, trim, and cover with bondo.

My brother and I did this very thing on an old S10 that he bought 3rd-hand from a guy that bought it 2nd-hand from the Navy (not well known for taking care of their vehicles). We sand-blasted all the really bad stuff (cab corners and the like) and blew the holes full of foam. Let it dry overnight, trimmed the foam, and bondo/paint the next day. Worked great for the 2+ years he kept the truck.