My house was built in 1955. I'm building a theater in my basement which has poured walls. The walls have no visible moisture coming through.

From what I have read, using a plastic vapor barrier is NOT recommended. This is because moisture can be trapped and form mold.

What I have read is to use extruded polystyrene no thicker than one inch that has no polypropylene or foil skins. I would glue this directly to the cement wall and put fiberglass insulation between my 2x4 stud wall before drywalling.

I would like to hear what others have done or comments on this method.

I Use the 3/4 in foam insulated sheets that are sold in 4 x 8' sheets in between the studs ( cut to fit ). Its certainly more expensive but worth the upgrade, and you should also consider putting moisture lock paint on all the concrete walls before you do anything, that stuff will stop like 10psi of water

Here is an excellent article

http://www.eere.energy.gov/buildings/building_america/pdfs/db/35017.pdf

Bottom line is 2" of foam against foundation+framing with unfaced fiberglass, no vapor barrier.


In my basement (1986 poured concrete - painted/sealed - no water) due to the already sealed (as good as paint is) walls, I chose fiberglass batts (unfaced) and a smart vapor retarder. It is notmally impermiable to water, but in high humidity (i.e., moisture in wall cavity) it becomes permiable to allow the wall to dry inwards. $150 for 1000 ft^2.

http://www.certainteed.com/CertainTeed/Homeowner/Homeowner/Insulation/Prodindex/Residential/MemBrainProdIndex.htm

Of course, all of this depends on your location and weather conditions. Ask your local building inspector if he is amenable to a casual conversation on the topic.

db

Dan:

That's exactly what I did(northern Illinois climate). Leave about an inch between framing and foam board.

I did similar after talking to Yost, the author of the article but recommended 1 inch xps.

Bottom line is 2" of foam against foundation+framing with unfaced fiberglass, no vapor barrier.

. . .
Of course, all of this depends on your location and weather conditions. Ask your local building inspector if he is amenable to a casual conversation on the topic.



The above is what I concluded too. although maybe use roxul mineral wool instead of the fiberglass batts if you want a little more sound proofing from the insulation. for more info see:

http://www.buildingscience.com/documents/primers/plonearticlemultipage.2006-12-05.5229931729/section-2-recommendations/ (very good!!)
http://www.buildingscience.com/documents/primers/plonearticlemultipage.2006-12-05.5229931729/section-2b-recommendations2014air ("One of the worst assemblies for basement walls from the perspective of mold and moisture problems is a foundation wall that is internally framed and insulated with fiberglass cavity insulation and covered with a plastic vapor barrier."
http://www.eere.energy.gov/buildings/building_america/pdfs/db/35398.pdf
http://www.eere.energy.gov/buildings/building_america/pdfs/db/35017.pdf
http://www.buildingscience.com/bsc/resources/foundations/Understanding_Foundations.pdf
http://www.buildingscience.com/bsc/resources/foundations/basement_insulation_systems.pdf
http://www.buildingfoundation.umn.edu/OCBasementSystem/ProjectReview.htm
http://ths.gardenweb.com/forums/load/basements/msg1013404110282.html?4
http://www.newsday.com/features/home/nyp-hsdr-082505,0,452831.column
http://www.housingzone.com/proremodeler/article/CA6358797.html
http://www.huduser.org/Publications/pdf/moisturehomes.pdf (p. 54, 84)
Fine Homebuilding No. 169 March 2005 p. 78
Fine Homebuilding No. 162, May 2004 p. 52
http://www.housingzone.com/topics/pr/build/pr04ca007.asp
http://www.housingzone.com/proremodeler/article/CA6404480.html
ICAA Technical Bulletin re vapor retarders "it is recommended that a vapor retarder not be used in a wall that is partially or fully below grade."]
http://www.buildingscienceseminars.com/2006/handouts/BSD-103_Understanding_Basements.pdf
http://www.lepageproducts.com/home_projects/project.asp?PID=43


and more info collected at:
http://www.wikibestpractices.com/index.php?title=Basement_Insulation