# Insulation after the fact



## thedudeabides! (Oct 24, 2011)

I am replacing the sheetrock of one my foundation walls in my basement and I noticed that there was no insulation between the studs, just a plastic vapor barior between the old sheet rock and the studs. In ordrer to isulate this properly without too much destruction, can I just insert 2' XPS foam in between the studs and be done with it. There is also about a 1/4 - 1/8" gap between the existing studs and the foundation wall. Can I just fill that with spray foam or is that needed? Thanks!


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## jklingel (Dec 21, 2008)

I'd seal behind the studs w/ the foam to block convective loops behind them. Maybe it's not a big deal, but while you are there... Then push the xps against the wall. Also, foam any gaps in the xps-wood joints. S-can the vapor barrier below grade, unless you are in a really, really cold place.


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## Windows on Wash (Aug 30, 2011)

+1 to jklingel.

Gotta make sure it is airtight.

Are the studs against the wall?


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## concretemasonry (Oct 10, 2006)

What part of the world are you hiding in since you did not post your location and that could make suggestions mare accurate for you.

All too often, people from warmer climates overestimate the real conditions and needs since they do not really recognize the thermal inertia of the soil, concrete and the fact that they do not follow the exterior air temperatures and take more than a "blanket" (pun intended) suggestion for a specific location.

What is a really, really cold place? I have been in a cool/cold place (-10F to -40F minimums with highs of 5F for several weeks before) and went out and was able to drive a survey pin in the soil because there was only 4" of frost in the soil that had an early 8" snow cover. This is an example of the thermal inertia and storage of heat and thermal stability from the soil and reflects the variability of insulation needs, especially the vague and professionally admitted arbitrary concept of a "vapor barrier" that is not very exact, scientific and can be affected by a coat of paint. - It is great to talk and pontificate about, but how much difference does it really make?

Dick


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## thedudeabides! (Oct 24, 2011)

Thanks for the replies. 

I live in Atlanta, GA. 

The studs aren't touching the foundation wall, but the gap isn't big enough to slide any foam behind it. I was thinking spray foam could cover that if needed.


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## Windows on Wash (Aug 30, 2011)

Don't need a vapor barrier down there and installation of one is largely incorrect.

I will help foster more mold growth than solve it.


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