timgeorge

Vapor Barriers

In my basement project I'm nearly finished with the rough-in and about put in insulation and close up the walls. I was curious about vapor barriers, and the need for them.

The basement room is 290 SF, has 2 1/2 exterior walls, is 2/3 below grade and was framed with 2x4's. Moisture on the walls hasn't been a problem since we redirected the downspouts and thoroughly cleaned the gutters.

Is it recommended to use a vapor barrier, or just insulation with paper backing?

bungalow jeff

A vapor barrier would go between the masonry wall and the stud wall to act as a moisture barrier for the insulation. A vapor barrier over the insulation will trap moisture in it, leading to mold spores.

Bruce H

bungalow jeff:
Would you believe that in the city I live in (suburb of Minneapolis) the building inspector required the moisture barrier like you talked about PLUS a vapor barrier on the warm side of the insulation. I argued myself blue in the face that this would create all kinds of problems, to no avail. Inspector had me stop the moisture barrier short of the plate at top of wall; the idea is that any moisture in the insulation can travel to the top of the wall and out. Of course the inspector doesn't have to live with any problems that may develop.

Bruce

bungalow jeff

Moisture travelling up? Oy. You should really try to get that repealed. Or at least tear it off before hanging the drywall after he has approved final rough-in.

timgeorge

Bungalow Jeff:

Based on the fact that the stud wall is up, would you suggest just using insulation without the vapor barrier?

As an option, should I paint the walls with a Dry-Lock paint?

I just (briefly) reviewed the Fairfax County code and doesn't seem to require vapor barriers.

Thanks

bungalow jeff

I think you have a good plan.