DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Insulation (
-   -   Insulating old walls top down (

_h9 04-19-2013 10:57 AM

Insulating old walls top down

I have access from the second floor to two fairly un-insulated exterior walls (on the first floor)
I am in Minnesota so it would probably be a pretty significant upgrade adding some sort of insulation.

My walls are "Insulated" with an airspace that has lathe and plaster on both the inside and outside. The interior has sheet rock over the plaster, and the exterior has cement siding. At the bottom between each pair of studs is a big hunk of plaster that is hard, resting on the sill.

I've thought about trying to find a foam insulation machine that will fill the cavities.
I've also thought about buying a few crates of "Great Stuff" insulation and just going to town with it. I would do this in a gradual process maybe filling a foot at a time if its from cans, I know it expands a lot.

Also considered pour-in or blow-in especially with how dry it is between the walls (from what I can tell). I've heard both settl and leaves air gaps.

I've also considered just re-sealing the space with solid foam and a layer of canned spray foam.

Just looking for suggestions, ideally I wouldn't have to rent a machine or something to do spray, but if its the right way to do it I'll consider it.

redman88 04-19-2013 11:29 AM

gut the walls and do it right.

_h9 04-19-2013 11:47 AM


Originally Posted by redman88 (Post 1162743)
gut the walls and do it right.

I guess thats more work than I want to do. In that case I will just reseal the air spaces with rigid foam

Seattle2k 04-19-2013 11:57 AM

If you decide to foam, make sure you use a low-expansion foam, so there's less chance of blowing out your walls. I wouldn't use GreatStuff or the likes. It's not meant to fill wall cavities and may not cure properly.

And, since you have plaster walls, do you know if you also have knob & tube wiring? Don't want to foam, if you do.

Here's a video showing DIY method of applying 2-part spray foam to a closed wall cavity.

_h9 04-19-2013 11:59 AM

If thats the black, double insulated stuff, that makes your hands filthy, then i've removed almost all of that and replaced it with romex. A lot of crawling on my belly in my crawlspace.

I'll look into the low-expansion stuff. Thanks for the suggestion!

Seattle2k 04-19-2013 12:02 PM

Just found this video.... Not sure if it was bad foam or some other proplem that caused it to shrink, but it's worth looking into further.

Uh oh, and here's another! I think I would just use blown-in insulaton. Take note, though, that there may be different types of spray foam insulation.

UPDATE: According to literature on he NACHI website, I think those videos may be showing UFFI foam, rather than SPF foam. Yeah, probably UFFI foam in those videos: and

_h9 04-19-2013 01:58 PM

Thanks for the replies. I'm looking at a low-expansion kit by "Tiger Foam" for $600. Might just be the thing.

All times are GMT -5. The time now is 04:34 AM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1