Doing research prior to attempting a DIY basement finish. Never had moisture issues (sealed prior to move in) since we've been here (10yrs), walls are all below grade (no walk-outs). no insulation anywhere other than the space between the top of the wall and the bottom of joists (terminology). The question is, can I frame the walls and use faced rolls, or do i need the boards, boards and rolls...no vapor barrier, vapor barrier? I'm in Zone 5 apparently. Also, currently no real heat in the basement as the HVAC was not setup that way, but that would change a little once we finish. Purpose will be an open space with part for workout/hang out and the other for wife's sewing area (which is where we would focus heating efforts).


  • There is a sophisticated site where all questions concerning dew points, moisture and drying time, U value, phase shifting and more are calculated and displayed. Best way is to open an example and change/add layers. Each layer can be easily switched on/off to instantly see any change. Toggling between R- value/U- value is done by clicking on the tool icon next to the result. It is free for private use. www.ubakus.com
    – xeeka
    Commented Feb 22, 2021 at 16:50
  • Watch youtube.com/watch?v=oKQdo88Ne74 by This Old House--they cover a lot of stuff just deep enough to get most DIYers on the right path, and this video covers your questions.
    – TylerH
    Commented Mar 24, 2021 at 19:39

1 Answer 1


I'd either go with rigid foam board glued and spray foam sealed to the concrete or spray foam. Depending on how much insulation you want you could then add some rock wool batts. Add 6mil poly with taped seams and then drywall. You'll need the air barriers around any outlets in the exterior walls.

The concrete is always going to be the coldest surface and any moisture in the warmer air of your house is going to come into contact with it and condense. You need both an air barrier and a vapor barrier (poly will work for both). I only go with moisture proof insulation against basement concrete wall in cold climate. You might also want to consider moisture resistant drywall for the basement walls to avoid having paper that can be used as a food source should the drywall absorb water.

  • thanks for the insight. still a couple months out probably. Thanks also for the reminder on the drywall. I had initially thought about it when i started designing the project, but then forgot about it when listing out the materials. It is now back on the list.
    – user130576
    Commented Feb 23, 2021 at 12:59

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