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Question:

vapor barriers-I have a house in cny with a plastic lining behind the sheetrock and I am getting wet walls.?

There is extreme wetness near the base of the walls 1 perticurally to the south and west and one to the north and west sides. I have had the attic ventilation balanced and it has gotten a little better. I also forgot that there is tyvek on the exterior and the cedar siding is curving toward the outside. I had the worst of it (siding) replaced this summer. The heat registers have just been replaced because they were rotted. I am replacing a sliding door for the same reason. I am also trying to replace some windows that may be leaking air. Thank you

Answer:

The plastic should be under the sheet rock and the insulation behind the plastic. The vapor barrier should go towards the heated finished side of the home. Your problem is the ceder shake siding that curves. I should always lay flat and over lap 6 to 8 inches. If you have any curving the water is getting behind them. Tyvek will not help this as there are tiny pin holes in it to allow the house to breath.
well im a contractor and theres not enogh imfo on this but i m better at seeing it . try to spray some water reppelant on outsid walls also check gutters and flashing onext. sides
HERE IN SE, TX WE HAVE HUMIDITY ALL THE TIME AND WE DO NOT PUT PLASTIC UNDER THE SHEETROCK THE ORDER FROM INSIDE TO OUTSIDE IS PAINT SHEETROCK WALL STUDS WITH INSULATION BETWEEN THEM OSB(OUTSIDE SHEATHING BOARD) TYVEK SIDING PAINT OR STAIN THATS IT. USING THE PLASTIC U HAVE CREATED THAT VAPOR NOT A VAPOR BARRIER. THE TYVEK DOES THAT JOB THE HOUSE IS SWEATING BECAUSE OF THE DIFFERENCE IN THE TEMP INSIDE TO OUTSIDE. THE FUTURE HEALTH ISSUES ARE MOLD AND DECAYING SHEETROCK
FYI - if your drywall has lready been exposed to moisture, it should be replaced. There is a new type of moisture, moldresistant and mildew resistant rock out there called Humitek. It is a few steps better than regular greenboard. It goes for abt $0.50 per sf so it's a little more expensive than greenboard, but weel worth it.
hey john t up here in the north east to keep the insulation from getting wet during the heating season we use vapor barriers. that said, it sounds like you are getting too much moisture in the house. do you have and use bathroom exhaust fans? do you use a exhaust fan that is vented outside when cooking? do you have a humidifier hooked up to your heating system and is it set too high? i think the heat from the sun is warming the walls and attracting the water vapor to the s and w sides of the house. it's either that or a roof leak as it has been pretty rainy year in the ne.hope these offer you some ideas on things to check and hopefully solve you trouble. good luck.

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