help! water condensating in the wall cavity-


Old 02-23-06, 12:17 PM
Thread Starter
Join Date: Feb 2006
Posts: 2
Unhappy help! water condensating in the wall cavity-

we are building a new home here in Iowa. we have 1 inch of closed cell foam blown in as an envelope and then the rest of the wall is filled with fiberglass blown in insulation. They did not put a vapor barrier up. The walls have been drywalled, muded, and painted. We had a really cold few days and now we see water coming out of our walls on the plywood floors. Other info.- geothermal heat is on, we have an air to air exchange. We think warm moist air from inside hit cold 1 inch of foam and condensation developed and now is running down foam onto floor. We are trying to figure out what to do?
options we have thought of 1- try to dry out with de- humidifier, heat up on high, and leave as is with primer paint and 2 other layers on drywall acting as a barrier now.
2- try drying, and paint on a vapor retarder paint.
3- rip off dry wall, try to dry, put up vaper barrier and redo drywall.
4- rip off dry wall, take out blown in fiberglass insulation, dry wall and spary they rest of wall space with more closed cell foam.
(questions - will condesation go away with fiberglass insul.trapping it there? will closed cell foam adher - attach to existing foam on wall????)
any info. help, experience on this matter is greatly appreciated!! THANKS
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Old 02-23-06, 02:29 PM
Join Date: Mar 2005
Location: USA
Posts: 6,126
help! water condensating in the wall cavity-

If your fiberglass got wet, it will not dry out and may have lost half of its insulating value. The only choice is to remove it and replace it AND put a vapor barrier between it and the warm, conditioned space.

I have seen a few hundred damaged homes in New Orleans and was amazed at how much moisture fiberglass can hold (attached to the fibers and not absorbed by the glass). It just does not dry out if it is not subjected to airculated, dry air. After a few weeks (months in some cases) of high humidity, the ceiling drop, exposing the mold. This is in homes with not discernable roofing damage.

Since your problem sounds severe and likely to occur again if the insulation value is decreased, I would suggest you cut a few observation holes in hidden areas of the external walls. If you are careful, you could patch them up easily. This will let you know what the condition of your insulation/wall is.

Old 02-24-06, 05:55 AM
Join Date: Jul 2005
Location: Ottawa, Canada
Posts: 857
Agreed with the above. Once the insulation is wet inside a cavity, there is no way it will dry out. Besides, even if it did dry out, you still haven't solved the moisture problem.

Doesn't your local Code require a vapour barrier on the warm side of the insulation??
Old 02-24-06, 01:09 PM
Thread Starter
Join Date: Feb 2006
Posts: 2
We are in the process of looking at a fire restoration company that is able to come in and with different methods, take out all humidity inside the walls. Also putting a device that can check humidity levels in the wall itself.
As far as finding the moisture problem - we know that the mosture came from the mudding, painting processes and running carosene heaters in house. Then came the big drop in outdoor temperature. Causing warm moist air to rush to outside wall hitting the cold 1 inch foam sprayed in. It basically happened b/c of extra moisture in house happening at the same time we get the very cold temp. In a normal home environment, even with all the water humans give off and create with baths etc.... we will never have that much humidity inside again.
thanks for the comments -
Old 02-24-06, 03:21 PM
Join Date: Mar 2005
Location: USA
Posts: 6,126
help! water condensating in the wall cavity-

If you are so aware of the cause of the problem, you are probably aware that is not limited to the walls. The moisture could condense on any cool suface such as roof trusses and other cool materials.

If you have those conditions and humidity, you take a must look at the rest of your home. Anything cool or cold would have condensation on it and probably would not evaporate soon enough. I have seen $1,000,000 homes ruined by the same conditions. Sheet rock stripped twice and wood "cleansed", but the mold spores could not be killed even though the mold disappeared.

Your worthless 1 inch of "funny foam" did not insulate well enough to to reduce the surface below the dew point of the air in the cavity. It provided a vapor barrier and a good place for moisture to condense on. With even the slightest leak in the moisture barrier, moisture will eventually accumulate in the unvented cavities. This will eventually reduce the insulation and problem will begin again. You construction process only sped up the cycle.

The odds on drying and salvaging the cheap pink stuff in place are next to nothing. If the old insulation is wet it must be stripped out and tossed.

Putting on another vapor barrier under the sheet rock could create the classic problem of double vapor barriers that must always be avoided. In your case, anything is better than fiberglass with another vapor barrier.

You best choice may be to hire a professional that does not sell any products to tell you what you have and how to solve the problem. There a number of solutions depending on your conditions. You should seek professional, local advice that can look at your home. Look for engineers that specialize in moisture control or moisture intrusion. Depending where you are in Iowa, you may have to look to a DEs Moines or Minneapolis/St. Paul firm.

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