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I am building a new home and have insulated the walls with 1" of foam and paper backed fiberglass insulation. After the contractor put up drywall he recommended plastering the ceilings and the walls for a better and harder finish. After this was completed and the plaster walls were dry enough, we started to paint.

During this time I noticed water leaching out from the bottom of the drywall. It was bad enough that it pooled and left brown water marks on the sub floor. The water shows up at different spots in the home for example, by the sliding glass doors, in the great room and master bedroom. All these areas are outside walls in a cold weather climate.(upstate New York) I have also noticed a lot of water on the interior of the windows especially while the ceramic tile was being laid and during the painting of the interior.

The house has vinyl siding, and has been wrapped with a blue Dow whole house wrap.

  • Is the outside of the house finished? Is the roof totally on and shingled? We need to know what stage this house is at. Where I am at drywalling is almost last. – DMoore Jan 16 '15 at 4:20
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To a certain extent, moisture is unavoidable during construction. However, this is why you don't build in winter, especially in your climate, because the surface temperatures of many smooth materials (your windows, tile, plaster) are going to fall below the dew point, especially if the heating system hasn't been installed yet. When that happens, any moist air nearby is going to condense on them and turn into liquid water.

Since you can't change the season, and you can't remove the surfaces that are receiving condensation, if you want to cut your losses, hurry up and install the heating system right now, or else insist that construction take place only in the presence of construction-grade space heaters and dehumidifiers to keep moisture down and the interior heated to above the dew point.

Finally, I hope you don't have poly sheeting under the drywall. If you do, it would be worth it to eat the cost of removing the drywall and the poly sheeting. This stuff is incorrect to install, as it is a smooth vertical surface that will receive a lot of condensation when it falls below the dew point temperature. A lot of moisture is present in adjacent materials during construction, and if it's cold out... do the math. Your walls are going to weep like crazy and present an ongoing problem.

More worryingly, it sounds like your general contractor doesn't really know what he's doing. You should not be building a house during a cold upstate New York winter, and your drywall should not weep during construction due to un-dealt-with moisture loads. Additionally, 1" of foam outside the sheathing is far too little for your climate, and kraft-faced fiberglass batts are the worst, lowest-grade insulation out there; they perform very poorly.

  • Thanks for your input so far!! The house is completed on the outside siding, roof and radiant floor heating has been installed and is running at 69 degrees. The insulation between the studs is 6" r25 paper backed and the 1" foam is on was applied to the inside of the outer sheathing between the studs.Also this is not mud applied to drywall but two layers of plaster base and smooth finish coat. Does that make a difference in terms of moisture leaching? – Brian Jan 16 '15 at 13:08
  • Unfortunately, you did it wrong. The thin layer of foam is supposed to be installed outside the sheathing, not between the studs. The way you did it is expensive, risky, and dangerous, but it's probably too late to rip it out if you paid a fortune for gypsum veneer plaster. A radiant floor is also a bad heat system for drying out the house because it necessarily runs at lower temperature than forced air or you'd cook your feet, which means less drying potential vs blown hot air. You nee to get heaters and dehumidifiers in there ASAP. – iLikeDirt Jan 16 '15 at 14:56
  • Thanks for your comments! Here in upstate NY no one has ever heard of spraying foam on the outside of the house on the sheathing rather than insulating between the studs, interesting!! Well I guess we will just try to dry out the house as best we can!!!!!! – Brian Jan 17 '15 at 12:06
  • You don't spray foam on the outside of the sheathing; you apply rigid boards of it. If you're saying that you had 1" of foam sprayed between the studs, that's a little better than if you had used rigid boards (because sprayed foam is airghtight to the interior of the sheathing) but still not ideal. You should have filled up the entire cavity with sprayed foam ($$$$) or not used any spray foam between the suds and saved your foam budget for putting rigid foam boards outside of the sheathing ($$), which would have been more effective anyway. – iLikeDirt Jan 17 '15 at 15:10
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A lot of moisture comes out of drywall mud after it is applied. I strongly recommend that you rent commercial dehumidifiers to dry the air out as soon as possible. (This is exactly what I did when I built a house and the drywall was installed/mudded in winter - even driving out to the house in the middle of a snowstorm to empty the reservoirs.)

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