Spray foam insulation in old home

BlueFox

Has anyone ever had an existing home insulated with foam? Is it doable? Easy? Any issues?

My home is stucco on the outside, and sheet rock inside, with no insulation in between. While I am interested in saving on heating and AC, I really want to cut down outside noise (boom boom cars, and outside music from parties), and prevent my stereo from being heard on the outside.

zane77

I've seen on a few of the DIY shows they usually use a blown in insulation that they blow in through a few holes. I think the expanding spray foam would have a tendancy to push the sheet rock off the wall.

unc2701

+1 on the above. I've never seen it done on a completed house. You can do top down with blow-in insulation via some moderately sized holes that are then patched, but I don't think you can do foam w/o bare studs. Friend did it for the floor in her crawlspace and it's pretty awesome, but I just can't see it happening with the drywall up.

zane77

I have a fairly new home and they used spray foam for all the insulation in my homes walls, really seals everything up. Watching them spray that purple stuff in such a thin coat and how much it expands is pretty cool. In a few places before they could put up the sheet rock they had to plane it down even with the 2x6 wall studs.

jbooker82

I belive the wall has to be open. Other wise it is like when you freeze water. The foam will grow and explode a wall. Ethire in or out.

BlueFox

I will call some companies tomorrow and find out. One web-site I was reading says the expanding foam takes the path of least resistance and expands up. I guess if you put to much in then it could expand out.

unc2701

Yeah, I really don't think that it would pop your drywall off (more likely it'll just compress itself and lose r-value), but i do think that it'd catch on the wall halfway down the space, expand and block it off (assuming you start from the top). Filling the whole thing would be a pain.

dkg999

A good installer with closed cell spray foam will use the right formulation so that it fills the wall cavities. They have minimal expansion foams for insulating existing walls. You just have to drill a bunch of 3/4" holes through your inside walls to get the applicator in. A good installer will have a camera that they will use to check the wall cavities for any obstructions or problems. The blown in cellouse insulation settles over time and becomes a dirty mess in the bottom of your wall cavities.

What you really need to consider is the cons of insulating your walls. Open wall cavities vent moisture out and preserve the stucco on the outside, and the vented wall cavities stay dry and mold free. Filling a wall cavity with any kind of insulation can create moisture problems. If you really look at heat/cooling efficiency, your ceiling and basement along with unsealed air leaks can be more of an issue. I'm not sure what else you could do for noise abatement.

steveinaz

Don't forget to think about where the fire-breaks may be inside the wall (2x4's running laterally between studs), if you have them. You might end up with a half-insulated wall. You'd have to go with "blown-in" type insulation.

mudwrx

I had some spray foam done, but it was in the basement crawl spaces. We had them remove the old, falling insulation (basically useless) from the ceilings and spray with foam insulation. Since it is in the basement crawl spaces the insulation is done for the floors/living area above.

We did not have any wall considerations you have, but the insulation is quite amazing. It gets in every little space. If needed it can be cut away after it cures (if you had to get to a pipe or something).

Good luck.

charley95

Check with the insulation contracter to see if there are any rebates involved from your utility company. I had $3000 worth of insulation done on my old house last fall for $600 after the energy saving rebates. I think the incentive was through the govt. with my local utility company. They may not do that out there where your at, I don't know. I also was able to write off 10% of material cost on my taxes.

Syndil

A lot of good info here, even if you don't use this particular company:

http://retrofoam.com/

BlueFox

This is like everything else; a chore.

After talking with the foam installer I found yesterday, he said they have pretty much stopped using foam since they were finding areas it didn't fill. He said that celloise actually works better for sound than foam, but that it settles after some number of years. I have an installer coming by tomorrow, so I can get an estimate, and pester with questions. PG&E does have a rebate program that should be worth $500-$600 for my home.

Syndil

BlueFox wrote: »

After talking with the foam installer I found yesterday, he said they have pretty much stopped using foam since they were finding areas it didn't fill.

A foam installer that doesn't like foam... I'd be looking elsewhere for advice.

BlueFox

Syndil wrote: »

A foam installer that doesn't like foam... I'd be looking elsewhere for advice.

I guess I should have said insulation installer. He said they will do it, but recommend against it.

wolfman1138

I looked into this for my 1920's house. I have not pulled the trigger yet, but there are several different methods. From my research, there are companies that will use sonar to estimate the cavity volume and pump in the right amount of stuff. Otherwise you can really damage the interior walls. I have lathe and plaster, so this is extra critical for me. The folks I talked to would remove one board from the siding and then replace it (obviously not an option for stucco). I also live on a busy street and the installers said that they wouldn't normally recommend insulating the walls in a house like mine, but the street noise was a good reason to do it.

As steveinaz said, fire breaks can also be a real issue. I have blocking at the 8' level of my 9' ceilings which is used as both a fire break and support for the picture rails.

Good luck!