OT construction ? concrete wall vapor barrior

The vapor barrier should be on the side of the framing closest to the occupied area. This is to prevent moisture from the house condensing within the insulating fiber material. Insulation traps "air" and keeps cold air from moving.... that won't happen if the insulation is saturated w/ moisture. The plastic sheeting on the studs, directly under the gypsum board, is correct.

The vapor barrier should be on the side of the framing closest to the occupied area. This is to prevent moisture from the house condensing within the insulating fiber material. Insulation traps "air" and keeps cold air from moving.... that won't happen if the insulation is saturated w/ moisture. The plastic sheeting on the studs, directly under the gypsum board, is correct.

The vapor barrier should be up against the concrete to avoid migration of water from the concrete to the room. In many areas, the ground can be considered 'saturated' and will continuously wick water from the ground into the concrete concrete block and then into the building.
An easy test for ground moiture is to cover a section of wall (or floor) with a 3' square sheet of plastic for a few days. When removed, the wall or floor should be dry (same color as the rest of the wall/floor). If not, you need to put in a vapor barrier.
Craig Suslosky wrote:

Nope, you want the vapor barrier between the moisture source and the insulation to keep the insulation as dry as possible. Even more important, you need to keep the wood framing dry so it doesn't rot. In cold climes, that means the vapor barrier is inside as you mentioned. Below grade it is reversed. The OP is below grade.
larsen-tools wrote:

I'd contact your local building inspector as the placement changes depending upon where you live.
Steve.

If he's got a leaky foundation, his problems are bigger than which side the vapor barrier goes on.

Doesn't have to leak. Around here, ALL wood in contact with block/concrete MUST be treated lumber due to moisture in the concrete. Closed cell foam is allowed in contact with concrete/block but not fiberglass bats and similar. If you put the vapor barrier on the sheetrock side, eventually the entire wood/insulation system will have the same moisture content as the concrete. Which is the same as the moisture content of the soil outside. Which is not supposed to have untreated wood in contact with the soil.
larsen-tools wrote:

"Amen" to that. Thank you.

The moisture barrier should be on the side of the wall facing the primary moisture source. This can vary by location, climate, and whether the construction is above or below grade.
Typically, for above grade construction in places where there is a winter, the vapor barrier should be facing the occupied part of the house. This prevents the warm moist interior air from infiltrating the colder insulation and condensing on it.
Typically, for below grade construction, the vapor barrier should face the concrete exterior wall. That stops dampness due to groundwater from migrating through the concrete and into the wall insulation.
But that's not always true. If the concrete wall was poured with a vapor barrier on the outside (dirt side) of *it*, then you'd proceed as if you had above grade construction and put the stud wall's vapor barrier toward the interior.
A test you can perform is to tape a 3 foot square of plastic directly to the concrete wall. Let it sit for a couple of days, then take it down. Note if the wall and the side of the plastic facing the concrete is damp. If so, the vapor barrier needs to go against the concrete. If it isn't, put it toward the occupied side of the stud wall.
Gary

NO NO NO NO! Gerry :-)} London, Canada

In this case you need damp proofing and proper drainage on the OUTSIDE of the foundation wall. Gerry :-)} London, Canada

On Mon, 18 Oct 2004 19:46:08 -0400, Gary Coffman vaguely proposed a theory ......and in reply I say!:
remove ns from my header address to reply via email
Your reply makes the mosts sense so far. Iy took a few words to explain fully, but the forst sentecne says it all IMO.
BUT. A serious question. Below grade, wouldn't it be worth putting a barrier on _both_ sides of the insulation? The room dampness / condensation problem will still be there, and cause problems with damp insulation/mould etc, just as as it would above grade.
***************************************************** Have you noticed that people always run from what they _need_ toward what they want?????

I'm in Minnesota, we have 8000 to 10,000 degree days of heating which drives the frost in 3' to 6' depending on snow cover. We also have an extremely heavy clay soil that does not drain well. Add in 25 or so inches of annual precipitation in one form or another and you need to deal with basement water.
You are correct, you usually put "damp proofing" on the outside. This is a really serious black tar goop, sprayed on hot by the pros, brushed on cold by the rest of us. It attempts to keep the concrete/concrete block from getting saturated with fround water. It's common to put a 2" layer of high density fiberglass on the outside of that to keep the frost at bay. You can't put foam out there because the asphalt mix will desolve the foam.
Standard new house/new footings in remodeling calls for damp proofing on the outside, drain tile ABOVE the footings on the outside, drain tile BESIDE the footings on the inside (both of these covered in fabric to keep the silt out and then covered with a foot or so of 1" rock. Concrete block gets the addition of foot long pieces of 1/2" ABS water pipe from EACH concrete block core to the inner drain pipe (every 8"). So much for depending on the damp proofing to do the job fully.
The concrete floor needs to have a vapor barrier either above or below the slab. Not required, really is useful to have it there.
THEN you put the vapor barrier in next to the concrete and go from there.
Old Nick wrote: