Therma-Stor Forum / Residential / Winter Condensation

Winter moisture problems in new attached garage

Vieth — Sun, 11 Feb 2007 08:09:03 GMT

For our new construction, the finishing of the drywall coincided with a winter cold snap, so I'm not sure which is to blame, but we have serious moisture problems in our new attached garage. The drywall is finished and textured, but there is not primer or paint yet, and frankly I can't see priming/painting with so much moisture. The bottom 2 ft. of drywall on exterior walls have soaked up water and the drywall is saturated there. There is also standing water on the cement slap all around the exterior walls, about 3 ft. in from the walls. I believe that is where the condensation is occurring, and the standing water is being soaked up at the bottom of the drywall. I should also tell you that, unlike a lot of new constructions, our garage does not have a 6" sill wall or water splash wall; rather the concrete foundation height is even with the slab. I was told this is allowed by code only for handicap-accessible garage slabs where the slab is even with the house's floor level. For us, it just worked out better that way due to the grade of the site and was not done for handicap accessibility, but nevertheless that qualified us for the low splash wall height, which we wanted in order to minimize the amount of exposed foundation on the garage's north elevation. So, since we don't have a splash wall and the drywall runs all the way to the slab (or about 1 inch from the slab), could this be what's causing the drywall to soak up all the condensation? Also, what's causing the condensation in the first place? Is it because we keep the house door open and warm air enters the garage and comes in contact with the cold garage walls? By the way, the garage is a 2x4 construction and it is insulated.

Here are some more questions.

1. At this point, with so much water in the drywall, what are the implications? Is the drywall ruined? Could it become ruined?

2. How can we get rid of this moisture? Heaters? Dehumidifiers? Fans? A combination? We've tried space heaters, but seems to have about as much effect as lighting a candle in a walk-in freezer.

3. Is there something that could/should have been done differently with the construction to avoid this? There is moisture barrier (plastic) covering the insulation and 2x4s before the drywall was screwed in place, but if that should have kept the moisture from wicking up into the drywall, then I imagine the plastic would need to have excess that sticks out underneath the bottom of the drywall, and that is not the case for the entire garage--just some spots.

4. I should also note that there are moisture spots along the entire garage where the exterior walls meet the ceiling, with one 4-in. spot wherever there is a roof truss. I suspect the roof trusses are conducting heat away from those points and cooling them so that the relatively warmer air in the garage causes condensation there. What does this imply? Is this normal for our situation, or are there construction issues that have caused this?

Thanks in advance for any helpful information!

- John

Condensation on windows, high humidity levels in new home!

krhorne — Fri, 15 Dec 2006 16:05:30 GMT

[b]We have a brand new 1400SQFT Ranch with a full basment. The basment is finished other then the space under the stairs(which is cement floor), the furnace room (also cement floor) and the trim is not done. We have Natural gas heating and a natural gas fireplace on the main level. We keep the heat at about 70-72 depending on the day.We are noticing condensation on all of our windows, some just near the bottom but 2 others a better part of the window has condensation.We have 2 bathroom fans, a kitchen fan and we frequently open the windows to reduce the humidity level. The humidity level ranges from 55-70 on most days unless we open the windows and run the exhaust fans to decrease humidity. It then reduces to around 45-50.We are thinking about getting an HRV system, but are unsure if this will work. There are no other areas of the house (that we can see and we've looked) that have condensation or mold. We have heard that dehumidifiers don't work that well in the winter, but being that the basement does have 2 rooms that are concrete floor, we are concerned that most of the humidity is coming from there?? Could this be possible? Or is it just because our house is so air tight? What option do you recommend? HRV or dehumidifier? We are at a loss of what to do next as we have been trying to do everything else like running exhaust fans and opening windows. As soon as we close the windows and stop the exhaust fans, the condensation on the windows starts again!Any info you can provide to help us make our decision would be greatly appreciated!Thanks![/b]

Attic Exhaust Fan Settings for Minnesota Winter

markin763 — Fri, 15 Dec 2006 15:11:05 GMT

Hello all. We recently moved into a 30 year old home in Minneapolis. We've been having TERRIBLE indoor condensation problems. We've got an indoor hot tub and steam room and both are used extensively, especially now in the cold winter months...My question is this...we noticed we have an attic exhaust fan . There is a control switch in the attic. We also have a humidifyer plumbed into the heating and cooling system. Are these fans typically wired into the central HVAC system? Do we have to set them separately? Obviously, with the hot tub etc. we probably don't need the central humidifier running...but what settings should our attic exhaust fan be set at if at all?

High Humidity in a "Leaky" house

stevetone — Mon, 11 Oct 2004 13:45:53 GMT

Most of the information I have been able to glean on improving indoor air quality has to do with newer, "tight" houses. I would like to know if the same technologies can be deployed to improve the air quality in an older, "leaky" house. My home is located in Stoughton, Wisconsin (just south of Madison, home of Therma-Stor). It is a 46 year old house, and from what I've seen up in the attic and down in the basement, there are numerous air bypasses and insulation issues to be fixed, which I of course will be addressing "in my free time" (whatever that is). Fortunately, the windows and walls of the house are in relatively "tight" shape (in my opinion only). However, my immediate problem, possibly somewhat related to the "leakiness" of my home, is one of winter condensation. When the outside temperature drops to 40 degrees or lower, every window in the house has condensation on the inside, even with the storm windows in place, and even including the 3 newer, low-e, argon-filled Anderson windows. This level of this condensation is such that by the middle of Winter there is black mold present on the bottom edges of the window frames, dispite us "mopping up" the moisture every morning. We have hot-water radiator heat and a separate ducted a/c system (in the attic -- ugh). The basement is dry. As you can gather from our climatic conditions, we rarely open windows in the Winter. We have been living here 3 years and now it is (finally) time to do something about this situation. So my question is: given that my house is not even close to being "tight", will the APD effectively lower the humidity in my "leaky" house? Or, does the current state of air infiltration in the home present a condition that needs to be corrected before (or in lieu of) a dehumidification strategy being deployed? Sorry for the long question. And thank you in advance to all who reply.