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antho177 10-12-2007 01:43 AM

replace vapor barrier?
So I thought I'de rip out some banged up dry wall, Patch it up and be done with it. Next thing I know, I've got the insulation down and most of the black, what I believe is called a vapor barrier, pulled out. I can handle the rebuild; but I don't know what to replace this cloth like lining with. Do I need to replace it? It's stapled to the studs, before the exterior brick wall.

Hube 10-12-2007 08:13 AM

A VAPOR barrier is normally on the inside face of the exterior wall studs,just behind the drywall.
A MOISTURE barrier is usually placed on the exterior side(to the weather) of the studs just before the exterior sheathing/ siding or brick.

I assume you are referring to a vapor barrier. Most Vapor barriers are of a 6 mil plastic sheeting bought in a roll at most bldg/lumber stores

antho177 10-12-2007 11:35 AM

now we're gettin somewhere. It's the exterior side, a moisture barrier. Between the studs and the brick. From what I've read, it should be semi-permeable. Can I use plastic?

Hube 10-13-2007 08:50 AM

no, DO NOT use plastic.

There are several types of moisture barriers on the market.(tyvex, tar paper,etc.)
See your local bldg store, they will have it.
Note; plastic vapor barrier, applied to the interior stud face of exterior walls, is meant to stop any humid air WITHIN the home from entering into the wall, thus causing mold, soggy insulation ,etc. within the studs' cavity.

Moisture barriers are meant to be installed on the exterior wall sheathing or in the case of a bricked home, it will be installed just behind so as to stop any ENTRY of moisture from the great outdoors from getting into the studs' cavity causing rot, mold, etc.

glennjanie 10-13-2007 10:07 AM

Welcome Antho:
When you replace the insulation you can use batts that have a vapor barrier on the inside. We don't want to make something too hard out of this.

antho177 10-13-2007 11:34 AM

Thanks for the replies. Very helpful. So If I can find "batts", it will provide a sufficient barrier? I should be able to get it at HD or Lowes?

Hube 10-13-2007 01:06 PM

You said previously it was on the EXTERIOR side ,between the studs and the brick, so you do not want a vapor barrier there, you need (as I mentioned in my earlier post)a moisture barrier (next to the brick) a MOISTURE barrier will BREATH, but a vapor barrier does not.
sure, we don't want to make this too hard to do, but to do it right should be # 1 on your list.

glennjanie 10-13-2007 02:02 PM

OK Antho:
Let's try this again. With the brick wall in place and the studs in place, its a cinch you are not going to install a house wrap. The least expensive and easiest to handle remedy would be 15# felt (tar paper). Put it in the empty stud space near the outside and staple it to the sides of the studs. There should be a 1" air space between the studs and brick but there are also brick ties so it will be difficult to thread anything into the air space. That will take care of the MOISTURE BARRIER.
Now, you are concerned with the insulation and VAPOR BARRIER. The big box store will have insulation in rolls to fit 16" stud spacing or 24" spacing. The roll is perforated at 4' intervals so you can tear off a BATT at 4 or 8' intervals. This kind of insulation has kraft paper all around it but on the side that says "This side to living space" there is a thin film of tar on the kraft paper (VAPOR BARRIER). It also has a paper flange on each side of the batt which can be stapeled to the face of the studs; or if you prefer, you can staple the flange to the sides of the studs. This will leave the face of the studs clean for placing construction adhesive to hold the new drywall. The glue stuck to the paper flange won't hold anything.
I wish you the best with your project.

patterrw 02-14-2008 11:41 AM


How did you make out with this...I am running into a similiar situation now, also in the SE (Coastal SC), and trying to find the best approach.

my construction is (from outsite in) Brick/morter, 15 lb felt paper (tar paper), 2x4 stud wall, and 3/8 in plywood interior sheathing??? there is NO insulation in the walls, and I am looking to add some...we are finishing the room into a 1/2 bath and laundry room.

What did you end up doing with yours?

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