# Condensation (water) in wall cavity



## AllanJ (Nov 24, 2007)

Are you sure you didn't have ice dam problems over the winter? Did you notice snow extra thick on the roof at the eaves?

Maybe you should delay the remodeling a few weeks, pull away the wall insulation, let things dry out, and see if you get it wet again from roof leaking from rain.


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## rhr802 (May 29, 2011)

Hi Allan J

Nope, no problem with ice damning and that wouldn't effect the gable ends anyway  Also no ice damning to me would say that everything is insulated correctly (no heat loss to make the ice)

I have everything opened up. Have fans and a dehumidifier running (it's about 80 in the space. Rained all night and no water inside. in fact its drying out nicely so I'm very confident there are no leaks. It must just be a moisture a problem from the inside. The real question, how to resolve it so I can close these walls up with confidence.?


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## Gary in WA (Mar 11, 2009)

1.How many HDD or where are you located?

2. Typar? or Tyvek?

3. Moisture behind the poly but no drywall air-sealing it?

4. How long did the framing have to dry before the poly install? 

5. Was the framing ever wet during construction?

Gary


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## rhr802 (May 29, 2011)

I'm in VT

Typar

Correct. I didn't have time or money to drywall before winter so the space was insulated polyed and heated. My builder says no drywall or some sort of wall covering is part of the problem.

The building was up about 45 days before the insulation was installed. I was painting caulking the outside.

We had a very rainy summer last year as well so the framing did get wet a few times before it was dried in.

Here's my game plan. I've run fans and a dehumidifier in the space. Everything is 100% dry. Any area where mildew had formed I bleached with 100% straight bleach. I also threw away any insulation that was even slightly wet and replaced with new. 

I'm going to reinsulate and poly everything again. I'm then going to sheetrock the office portion of the space and OSB the workshop portion of the space. I'll paint the sheetrock and caulk the OSB joints and paint that as well. I'll actually be working in the office portion of the space so the computer equipment should help keep it warm and dry. The heat will also be at 70 rather than 45-50. I'll Keep a dehumidifier in there as well to regulate the humidity.

In the workshop space I'll have a dehumidifier on guard to control the moisture level and also set the heat to 60 or so rather than 45-50. Also, all winter I was keeping a small Kubota tractor in the workshop space that I use to snowblow. The snow would melt onto the floor and I'd sweep the water out once the tractor had thawed. I'm thinking this in conjunction with the typical extra 1st year moisture put way to much moisture into the space and with nothing over the poly to buffer it it was more than it could handle. My fault really.

After running the dehumidifier for just one day I'm amazed at how much drier the space is.

I'll let it go like this until next spring. At that point I'll pull a sheet of the OSB and check the wall cavities for excessive moisture. I'll also cut a hole in the sheetrock and test a bay there. If all is good then I'm home free. If it's wet like it was this year I'll pull the OSB (screwed on so that will be easy) and the sheetrock (that will suck but it's only 3 small walls). Pull the fiberglass, let it dry out again and then just foam the walls and that should solve any problems. Fingers crossed all is fine next spring but if not at least it's still savable. It will just require more work?


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## Gary in WA (Mar 11, 2009)

VT is Zone 6: http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_11_sec001_par001.htm

Type 1 or 2: http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_6_sec001_par003.htm

http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_11_sec001_par001.htm

I would have used faced batts. The framing got wet, sucked up the water like a sponge, now it’s coming out. At the top of the wall because that’s the warmest (driest) as heat rises in the air permeable insulation--- fiberglass, due to convective loops; http://www.diychatroom.com/f98/biggest-loser-fiberglass-insulation-90438/

The type of heating system added more interior moisture. It went through the wall trying to get out because the poly wasn’t air-tight, sealed with caulking as you should do to the drywall: http://www.buildingscience.com/docu...rs/air-barriers2014airtight-drywall-approach/

What type of siding?

Any rain-screen?

OSB? On outside and inside?

OSB and foam is not good: http://www.buildingscience.com/documents/insights/bsi-038-mind-the-gap-eh/?searchterm=foam%20board%20in%20walls

http://www.nrc-cnrc.gc.ca/eng/ibp/irc/ctus/ctus-n32.html

It takes way longer to dry: http://alcor.concordia.ca/~raojw/crd/essay/essay000129.html

http://repository.tamu.edu/bitstream/handle/1969.1/4625/ESL-HH-04-05-25.pdf?sequence=4

Optimum drying range- - 18-25 perms; http://www.energy.ca.gov/2007public...achment_14_Impact_of_Title_24_Residential.pdf
Tyvek= 58 perm.
Typar= 16 perm. = below minimum.

Painting the backs is a waste of time/money. You would need an oil-base or v.b. primer for the face, but pull the poly off if not required by your local AHJ. 

BTW- straight bleach is not as effective as 10% beach solution or a mold fighting solution without bleach.

Gary


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