# Insulating old walls top down



## redman88 (Oct 5, 2012)

gut the walls and do it right.


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## _h9 (Apr 19, 2013)

redman88 said:


> 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


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## Seattle2k (Mar 26, 2012)

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.
http://www.youtube.com/watch?v=KCNa6zb6x4U


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## _h9 (Apr 19, 2013)

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!


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## Seattle2k (Mar 26, 2012)

Just found this video.... http://www.youtube.com/watch?v=ieLm9NwE22c 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! http://www.youtube.com/watch?feature=endscreen&v=zKs2AQT-2gs&NR=1 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. http://www.nachi.org/uffi-insulation-inspection.htm Yeah, probably UFFI foam in those videos: http://www.3news.co.nz/Foam-insulat...homes/tabid/369/articleID/166991/Default.aspx and http://www.branz.co.nz/cms_show_download.php?id=e12348dba20e42d4dfbf2118c5504c58456067a6


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## _h9 (Apr 19, 2013)

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


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