Replies

1. 
   MSA1 | Jan 11, 2005 06:32am | #1

   i'm no expert on this subject, but i've seen the result of vapor barrier on the wall (brick in this case). The basement had a slight leak and was damp in general. The moisture collected on the wall peeled all the paint off. The whole basement smelled mildewy. Is your basement dry? I've seen new basements with simply an air-gap between the framing and the cement and then fg in a 2x4 wall. I've also seen rigid attached to the wall itself then framing. If you use a vapor barrier at all I would say the warm side. Good luck, i've actually wondered myself which method is the most effective. 

2. 
   cso | Jan 11, 2005 07:10am | #2

   There is a thread a few topics down on insulating block walls.  I am in Michigan also and have the same interest only with a block wall.  I was originally going to paint the wall with Drylok or other water proof paint and then throw up a stud wall, but now I want to know more.

3. 
   billyg | Jan 11, 2005 07:30am | #3

   See here:
   http://forums.taunton.com/tp-breaktime/messages?msg=52017.8

   Lots to think about.

   Billy

1. 
   tlbach | Jan 11, 2005 08:27am | #4

   thanks for the link.  I have to say the article raised more questions than it answered for me but I enjoy the education and I will do more searching.

1. 
   Hubedube | Jan 11, 2005 04:13pm | #5

    There is a difference in a 'moisture barrier' and a 'vapor barrier'...Moisture barrier can be applied right on the concrete wall (15 lb roof paper, it can breathe) this moisture barrier will prevent any moisture seepage that may enter from the outside. This also protects the insulation from dampness.(wicking)

    The Vapor barrier ( 6 mil poly, it does not breathe) is applied on the face of the studs (heated side) and prevents the room air vapor from entering into the wall and thus ruining the R value of the insulation. The vapor barrier also prevents the formation of mold, rot, etc ,(wicking)from occuring within the wall.

    If your 100 % sure that no moisture can enter from outside (dry concrete wall) then the moisture barrier can be eliminated.

   But the Vapor barrier on the heated side of the studs (next to drywall, etc) is essential.

    This reliable method is used throughout in many, many parts of  cold  winter areas.

    

1. 
   RBean | Jan 11, 2005 07:54pm | #6

   One of the top sites addressing your topic.

   http://www.buildingscience.com/resources/resources.htmRBean

   http://www.healthyheating.com

   http://www.healthyheating.com/blog

    

    

1. 
   MG911 | Jan 11, 2005 08:43pm | #7

   Hi all, I had this question also but everytime I went looking for an answer I was getting more confused.  I have already framed my 4ft concrete wall and added electrical as in the original post. The upper 4ft is existing drywall. (I live in an older 1959 - 4 level split and this is the level half above/half below grade).  I also live in a very cold winter climate (-41C with windchill today!!).

   A commercial framer insisted I have 6 mil poly against the existing concrete AND on the warmside of the insulationbefore I drywall - almost encapsulating the insulation for this type of remodelling.   I also had one other person tell me to slash the poly on the concrete side but not on the warm side and that the previous person was completely wrong.

   Looking at the concrete, there is no evidence of any water problems since the house has been built. What is the harm in having both sides of the insulation poly'd?  In the remote chance of any outside water leaking in, the insulation would be kept dry. Not sure how any moisture would eventually dissipate however.

   Sounds like there is much confusion on this issue...

2. 
   AndyEngel | Jan 11, 2005 08:53pm | #8

   This is an incredibly confusing topic, because the moisture sources vary, and the drying potential is limited. I've got an article on this topic in the issue of FHB that's now at the printer. All the science behind my article came from Joe Lstiburek's Building Science Corp. As one other poster suggested, go to buildingscience.com, search on "finished basement", and if you're like me, find out why most everything you ever thought about finishing basements was wrong. For example, there is probably no appropriate place for a vapor barrier inside a basement.

    

   AndyAndy Engel

   Senior editor, Fine Woodworking magazine

   Other people can talk about how to expand the destiny of mankind. I just want to talk about how to fix a motorcycle. I think that what I have to say has more lasting value. --Robert M. Pirsig

3. 
   RBean | Jan 12, 2005 05:43am | #9

   My favorite quote:

   "I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be." Lord Kelvin

   and Joe and the folks at BSC know the numbers.

   Its one of my favorite sites (next to this one of course!)

   RBean

   http://www.healthyheating.com

   http://www.healthyheating.com/blog

    

    

   Edited 1/11/2005 9:46 pm ET by RB

4. 
   DanMorrison | Jan 12, 2005 07:11am | #10

   There's the article that you wrote (which will be on the newstand in about a week) and there's also an article in #160 called "Does Fiberglass Insulation Still Make Sense?" with an illustration showing "Good" and "Better" insulation systems for basements, walls, and ceilings detailed by three of the country's leading building scientists, Dr. Joe among them.  Also see issue #162, "Built Wrong From the Start" for a brief discussion about vapor barriers in basement walls.

   But Andy knows that (don't you Andy?), I suppose I wrote this for the BTer's benefit...

    

    Dan MorrisonA happy associate editor