Fixing Basement Insulation

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Posted by: from Toronto
12/16/2018 at 8:54:11 AM

Hi, I recently opened up some walls in the basement and found that it's mostly insulated with 2" rigid foam tiled with gaps between each board section. There are black moisture barrier sheets against the concrete and no vapor barrer over the studs. There is a large air gap between the studs and concrete because the ledge is 6" deep and it's framed with 2x4 studs.

In addition the basement was underpinned and there are 6x18" tall concrete ledges along many walls. The walls are framed on these ledges and the drywall is butting up against concrete on the bottom 18" at the floor (there is the black paper there too).

Is adding rockwool in the studs with no vapor barrier going to create potential mold issues?

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Date/Time12/16/2018 at 6:07:24 PM

I recommend you have spray foam 2 lb insulation sprayed between all your 2" 4" stud walls. If you're using batt insulation then you will need to install a 6 mil vapor barrier to the warm side of your basement. Make sure Vapor Barrier goes over your concrete Ledges as well before you install drywall

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Anthony in Toronto
Date/Time12/16/2018 at 8:24:18 PM

Thanks Jeff!

If I spray foam would I need to just have the whole concrete wall covered?

(The studs are 3-4" offset from the concrete.)

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Sam in Mississauga
Date/Time1/2/2019 at 1:37:41 AM

After moving in our new home, I had accidentally opened up some walls in the basement. somewhat same trouble as yours. With hardly any knowledge of the technicalities of home insulation I decided to ring up the local professionals suggested by one of my neighbours. They turned out to be really good and solved the problem quickly. And they suggested a few ways to prevent mould growth.

Try calling in some professional near you instead on trying to manage it on your own.

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