Replies

1. 
   Guest_ | Dec 11, 1999 06:14am | #1

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   We do not build many basements here in NC, so I do not have much first hand experience with finished basements, however, from reading Breaktime, I have learned that installing the vapor barrier on the (potentially) damp side (between the studs and the masonry wall) is the way to go.

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   Thomas_Boardman | Dec 12, 1999 04:29am | #2

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   My understanding (but I am a carpenter not an engineer) is that moisture barriors go on the cold side of the wall and vapor barriors are installed on the warm side of the wall. Moisture barriors allow no more than 5 perms to pass through while vapor barriors allow no more than 1 perm. It has to do with warm air (and any moisture it may carry) condensing when it cools, as it moves from the inside of the house toward the outside. You don't want any moisture vapor to pass through your inside wall covering and condensing inside your walls. This could cause mildew or dry rot.

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   G.LaLonde | Dec 12, 1999 04:50am | #3

   *Ryan, First of all, you must make sure that you don't have any moisture penetrating your walls from the outside. If you do, I would forget about trying to finish them off from the inside. That said... I think the best way to insulate a below grade basement wall is to apply foam insulation directly to the concrete and seal all the edges. This allows the surface of the wall to stay relatively warm and you won't have condensation on it. It is almost impossible to keep interior moisture from getting past your 2x4 wall. If you insulate that wall, you are creating a cold space behind it where moisture can condense. The foam will provide plenty of insulation. Leave the insulation out of the 2x4 wall.

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   Riskiy | Dec 12, 1999 01:55pm | #4

   *Vapor barriers ALWAYS go to the warm side. Here, in Minnesota, we have alot of basements. I've installed all manner of insulation and framing against sub-grade concrete. The vapor barrier, (usually 4 mil fire treated poly)goes on just before the drywall. However G. LaLonde is right. If you have moisture penetrating from the outside you shouldn't cover those walls. How do you tell from moisture penetration and interior condensation? Easy, dry off a section of wall and tape a piece of poly to the concrete wall completely around the edges with duct tape. In several days, if the wall is wet under the poly you have penetration. If dry underneath it's just condensation.

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   ryan_wells | Jan 05, 2000 01:15am | #5

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   Hi i've got a qestion! when installing vapor barrier in basement with 2 by 4 framing against sub-grade concrete walls should the vapor barrier still be placed on the warm side? somebody must know!