Hi, I’m a general contractor with a customer who would like the basement finished. 1/2 inch drywall was selected to be installed on 2×4 wood studs. The question of importance is wheather or not to install a plastic sheet against the cement block walls. The customer feels that something should protect the drywall from moisture and that a plastic sheet would be the easy and the least expensive. I’m concerned about a condensation problem behind the plastic. Any advise would be helpfull. The basement is and has been dry for some years now.
Thanks in advance.
Michael
Replies
Greetings Michael,
As a first time poster Welcome to Breaktime.
This post, in response to your question, will bump the thread through the 'recent discussion' listing again.
Hopefully it will catch someones attention that can help you with advice.
Cheers
'Nemo me impune lacesset'
No one will provoke me with impunity
Hey Mike,
Check out the Building Science Corporation at http://www.buildingscience.com. They have some good research on sealing finished basements.
Thanks for the info WingNut. I wrote down the site and will review it. Thanks again.
This is one of those topics the gets people going like truck model or sawzall brand.
There are a number of ways you can approach this. Without delving into the 20 you aren't thinking about, what she's suggesting is ok. You put the plastic sheeting from the sill down to the floor, and under the bottom plate. Stand your studs off the wall enough that they're not touching it, unfaced insulation in the studs.
Depending on what you have to work with overhead, and since it is a basement, steel studs might make a whole lot of sense.
"A bore is a man who, when you ask him how he is, tells you." -Bert Taylor
Check out the No Mold Finished Basement article in the Feb/March 2005 issue of Fine Homebuilding. You can probably download it for about $5 at FHB's main site.
Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
Ditto what Andy said. (Of course he wrote the article)
In 2004 I framed a house for a general contractor that asked me to put plastic behind the studs in the basement. I did, and the insulators put in fiberglass bats. 4 months later I got a call from the general contractor. It was now winter and the home owner saw water dripping from the head casing on one of the windows in the basement. I went over to the house and started poking around in the basement and found that there was condensation in the stud cavities and behind the plastic. When we started digging a little deeper we found MOLD!
I'll cut to the chase. That incident cost the g.c. about $20k and he had a haz-mat truck sitting in a driveway in the middle of his sub-division.
Once the mold was taken care of we sprayed poly icynene foam in the studs and in the box beam. That eliminates the chance for warm air to reach the cold foundation. The g.c. made this his stanard practice.
That's a great approach.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
I like the approach that you show in your article about this subject. Especially the way you did the floor. Then again, I like the approach you show in most of your articles.
Thanks for that. I can't claim to have originated the ideas, though. I just put them into practice. I do think it's a great approach. About the only improvement I might consider would be be to replace the rigid foam on the walls with an open cell foam like icenyne.
FWIW, that was one the most popular articles ever in the magazine. I must have answered 100 emails, and even had several, very nice and apologetic, people track down my phone number and call me at home. Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
Wow, Guess plastic is not the way to go. How about not using anything? The customer does not want to go to the extra expense of insulating the walls.
m.
I'm located in NE Iowa. We are required by code to insulate the basement walls in the city where this house is. The crazy thing is that the code in a near by city states that the vapor barrier should be between the framing and the concrete wall. Thank goodness the inspector does not inforce that code because he knows what will happen.
Wow, thats harsh! Where are you located??(might help to update your profile)
either completely seal it ...
or let it breath and dry if necessary.
me ... I'd do either the AndyE way ... even though I did it that way before he wrote that article ... or ... no plastic.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
Insulation and a vapor barrier is a good idea, depending on the climate in which you live. If you live in a very moist climate, foam insulation with no vapor barrier may be a good idea, it will allow the walls to "breathe", if you live in a dry climate, R-14 batts, with a vapor barrier is the easiest, but definately use insulation of some sort to create a thermal break.
Wow, thanks to all of you guys that responded. I certainly am better informed from all of your knowledge. That is what I'm trying to do. Deliver better work for my customers. Thanks all again.
Michael
The article mentioned by Andy Engel is great though I have made a few changes to the method. I place 1 1/2 white strafoam (a product with a grey coating on the warm side form Home Depot) over the entire wall glued and taped., I then use 2x2 and strap them over the styrafoam screwed and pluged in the block or concrete wall. leave the drywall a good 1" off the floor .You will need narrow electrical boxes for the switches and plugs. I have done four basements using this and it is fast and the drywall can breath.
For the floor I use a product sold in Canada called Delta flow a grey dimbled plastic over a the well swept and washed concrete floor then place 5/8 plywood over screwed down with concrete screws about 20 per sheet.
this method really works well and impressed several builders when I suggested we do the basements using this method.
I should thank Andy Engel for suggesting the method.
George