# basement insulation - vapor barrier help please!



## Gary in WA (Mar 11, 2009)

Welcome to the forum!

Something to chew on; http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_6_sec001_par003.htm

http://www.buildingscience.com/docu...rol-for-new-residential-buildings?full_view=1

http://www.buildingscience.com/docu...ion/files/bscinfo_511_basement_insulation.pdf

Gary


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## cluelessloser (Apr 7, 2011)

Thank you for the reply.

It seems everyone has conflicting views on this issue, but it does seem that the best way to have gone would have been to attach and seal foam boards to the wall, then put the frame up against that.

I have read that with the setup I have now, since the plastic is touching the cool concrete block wall, condensation could happen on the inside of the plastic and then be absorbed by the insulation creating mold. Does that make sense?


Some people seem to think i'd be fine the way it is now and others act like it could not be worse. It is very confusing.

I think I can at least take down the drywall sheets and remove the paper facing from the batt. Everyone seems to agree that having the paper in basement walls is a bad idea.

If I were to put foam board against the cement block now it would be a big hassle since electrical outlets/wires and drywall are already in the frame.

Do you think it is worth removing all that?


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## Gary in WA (Mar 11, 2009)

I would. The plastic will stop moisture leaving the basement and grow mold on the resin holding the fibers together in the batts. I guessing, no sill sealer under the p.t. plate to stop any air/capillary/thermal break, low density (R-11) 3-1/2" batt insulation inherent with convective loops, and no foam board air sealing the rims; http://www.diychatroom.com/f98/biggest-loser-fiberglass-insulation-90438/

This from my other post; Check around at different web sites to compare information on basement finishing. A few examples; http://www.terrylove.com/forums/show...or-my-basement

http://www.greenbuildingadvisor.com/...ent-insulation

http://www.familyhandyman.com/DIY-Pr...-By-Step#step2


Gary


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## AllanJ (Nov 24, 2007)

Short of putting hermetically sealed foam of sufficient R value on the wall, there will always be room air moisture condensing on the "far side" -- on the concrete foundation, on a plastic sheet hung on the concrete foundation, on a thinner foam insulation board with infiltration of non-hermetically sealed joints, etc.

One of the recommended methods is having rigid foam insulation against the wall first. Another is an air gap of about an inch between ordinary fiberglass batts and the concrete wall.

Still, the front side (against the drywall) should not have a moisture barrier or in the case of faced batts, numerous holes should be cut so any moisture that got in can reasonably easily evaporate back out during the summer when the wall isn't as cold.


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## HomeSealed (Jan 3, 2008)

Clueless, GBR has got you covered. The only reason there is conflicting info is because some is outdated, and some is flat out incorrect. The most up to date, best practices can be found in GBR's links.


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