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Last year I decided to let my brother-in-law finish my basement. After he finished the framing he moved away. Now I have wood framing complete and nothing else. He claimed he knew what he was doing, but after doing a lot of research I am finding that he may have been premature putting up the framing. I've decided I'm going to finish the job myself but I have a few questions.

The previous owner put in a new basement about 20 years ago with metal support framing and all. The foundation walls are block and covered with a few coats of Drylock. In the 15 years I have lived there I have never seen water.

I'm starting to think foam insulation should have been put up on the inside of the foundation walls; between the framing and foundation. I should be able to sneak the insulation in there since my brother did leave an inch of space. Should I do this? Is there any special type of insulation and/or adhesive I should use?

Am I right in thinking Foundation Wall->Foam Insulation->Gap->Framing->Sheet Rock? Should I use moisture resistant sheet rock? IS any other type of insulation necessary in there? Is plastic vapor barrier necessary?

My brother-in-law also used green treated lumber where ever the framing touches floor. Will that be sufficient against moisture?

Thanks for your help!!

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    Here's how I did it in MN: diy.stackexchange.com/a/8644/1209 I used the method you outline (which seems to be the preferred method these days) – DA01 Feb 3 '15 at 17:27
  • DA01: I've read your post two or three times now. Very informative. My problem was that the framing is up already. Squeezing the sheets of foam insulation between the framing and foundation wall would be a chore, not to mention adhering them. I'm just wondering if it's absolutely necessary or if there is something else I can do that will accomplish the same thing without the chore. – Craiğ Manske Feb 3 '15 at 17:46
  • If you want to keep the existing wood framing, then you're going to likely need to fall back to the old-school way and use some batting insulation. Or--if you have the budget--spray foam, which would be ideal. But if you want it done 'right', it may be worth the effort to remove what's there and start fresh. – DA01 Feb 3 '15 at 17:51
  • Oh, and re: my previous post, if you decide to go with the foam trim, Menards is where I got it from. They had a huge selection of styles and profiles that I haven't seen at Lowes or Home Depot. I miss Menards at times. :) – DA01 Feb 3 '15 at 17:56
  • @DA01 - I just got interior doors at Menards... holy crap they had MDF framing which I did not notice until I got home... Attaching a door to a wet noodle. But they do have different things than the others but not always better. – DMoore Feb 3 '15 at 18:30
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There are no red flags that I see in your question. I don't like drylocking walls that will be covered in basements for the simple fact that if water hits concrete I would rather it go through the concrete than sit in the concrete (where if it freezes then expands will help promote larger cracks). But you have 15 years there and nothing so good for you and with that track record I wouldn't worry about it.

I would personally run roxul in joists and then down a good foot or two below grade, with no vapor barrier (you already have drylock). So what you have is insulation that does well in basements with drylock on one side and probably a decent air gap on the other and below. Would spray foam be better... maybe. It might insulate slightly better but then it is a mess if you do have a problem getting electric/plumbing out of the foam.

Moisture resistant sheet rock? It doesn't matter unless you are having a lot of water gun fights in your basement. The greenboard protects moisture from getting in the front (a little). Any long-term moisture from the rear will effect it like it would regular drywall.

Treated lumber? Perfect. He could have used treated lumber for everything but not required.

You sound like you are off to a good start. If you have more questions let us know.

  • If I understand correctly, you're saying the roxul should be touching the drylocked foundation wall from between the joists to about 1 or 2 feet below ground level? Then the framing and then sheet rock? – Craiğ Manske Feb 3 '15 at 17:52
  • For drywall, I'd avoid the green/blue board and go with something like Densarmor which doesn't use paper backing. – DA01 Feb 3 '15 at 17:52
  • Roxul sounds like a good compromise to dealing with what's already there, though. Good suggestion! – DA01 Feb 3 '15 at 17:54
  • Yes on the insulation questions. And then sheet rock or even better would be Densarmor as suggest by @DA01. I would not do greenboard (as when it molds it is actually worse than sheet rock). Your order right now should be - electric, plumbing, insulation, drywall. DA01 has a really good question/example and his basement might last 150 years but I am sure yours will make it long after someone wants to remodel or your house falls over. – DMoore Feb 3 '15 at 18:28
  • I think I'm going to look at the roxul. Thanks!! – Craiğ Manske Feb 3 '15 at 19:03

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