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So I know this is kind of a rabbit hole question -- mostly because I've been down that hole for the last month reading articles that disagree with each other. I'm hoping the folks here can give me a more practical answer..

I live in Maryland, so it does dip below zero on occasion here. My basement is all concrete, and I've never seen a drop of water. Realizing that concrete sweats (even if I can't see it), my plan is;

  • put up 3/4" EPS
  • fill the walls with standard insulation
  • cover with a plastic moisture barrier sheet before putting up drywall
  • Dricore subfloor

My question is basically; is that the right way to go? Do I need to change anything to make sure I stay moisture/mold-free?

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  • When you say "standard insulation". Do you mean unfaced fiberglass insulation? You're basically wedging fiberglass insulation in between two vapor retarders/barriers with the EPS and then a plastic vapor barrier--most insulation manufacturer installation instructions that I have read recommend against multiple vapor barriers.
    – statueuphemism
    Commented Sep 28, 2017 at 14:21
  • Also, what methods/materials are you using to frame the walls? Regular wood = mold food.
    – statueuphemism
    Commented Sep 28, 2017 at 14:26
  • @statueuphemism Yes, EPS, then fiberglass (or perhaps blown). Code in MD says pressure treated 2x4 for the bottom plate, and regular 2x4 for the rest, so that was my plan..
    – XeroxDucati
    Commented Sep 28, 2017 at 15:13
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    Have you considered using metal studs? They will not harbor mold, are lighter to work with, and they won't warp or check like wood which means you're guaranteed a straight/smooth surface for hanging drywall.
    – statueuphemism
    Commented Sep 28, 2017 at 15:42
  • @statueuphemism I have actually, but I keep reading you gotta fill the channel with wood or mounting things to the wall winds up having problems?
    – XeroxDucati
    Commented Sep 28, 2017 at 15:46

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I would NEVER put up plastic on the outside basement wall. All you will do is trap the moisture in the wall and create an environment perfect for mold. Especially with batt or blown insulation behind it.

EPS actually breathes water vapor and is better than standard insulation for vapor passage.

Moisture from the wall has nowhere to go but through the wall and needs to dry to the inside. The ground outside is already full of moisture so it can't dry to the outside.

Check out this website dedicated to building science.

Read the various articles on vapor barriers and mold. These articles are written by experienced individuals, some with PhDs in building construction like this guy.

These people know a lot more about construction than any site I have ever seen.

Good Luck!

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    If I could vote up multiple times I would. Your links to the Building science site is the same outfit that the company I used to work for 22 years teamed up with this guy to develop renovation techniques for weather and basement damp proofing. Met and did a seminar with Dr. Joe.
    – Jack
    Commented Sep 28, 2017 at 15:11
  • I've actually been reading this site a lot :) I just can't translate the PHd stuff to my application. Are you saying just EPS, fiberglass in the walls, and then drywall? And let the moisture dry thru the drywall into the basement?
    – XeroxDucati
    Commented Sep 28, 2017 at 15:13
  • I think on that site they recommend EPS and batter boards with moisture resistant drywall (greenboard). No fiberglass, plastic sheeting, or cellulose.
    – ArchonOSX
    Commented Sep 28, 2017 at 16:08
  • @XeroxDucati just EPS. Don't use fiberglass (no real point). I also recommend using paperless wallboard (densarmor).
    – DA01
    Commented Sep 28, 2017 at 16:15
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    @ArchonOSX what's a batter board? Are you talking about just putting 1" furring strips right into the eps/concrete without bothering with framing? If so, how would things like power outlet boxes get mounted? and how would wiring get run?
    – XeroxDucati
    Commented Sep 28, 2017 at 16:18

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