Insulation, Radiant and Vapor Barriers - Mistake adding fiberglass insul. over vinyl backed insulation inside shop.
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DW in Id.
11-29-07, 08:04 PM
My recently finished shop has the normal white vinyl backed insulation that's used in many shop buildings, but it's only 2" thick.
I'm finishing up a 12x16' room inside the shop. The room is in one corner so two of the room walls are on outside walls.
I'm adding additional R-13 insulation to the outside walls and I've also put it in the inside walls along with R-30 in the cieling. Both the R13 and 30 have NO vapor backing, just plain fiberglass bats.
After installing the R-13 in the outside walls and (luckily) after only 2 pcs. of sheetrock were on those walls, I noticed a heavy amount of condensation on the vinyl backing of the original insulation, underneath the new R-13 fiberglass I'd added.
Talking to a few local insulation people, a couple of them had no clue as to why I'm getting the moisture. One person that seemed very knoledgeable told me that I need to destroy the vinyl on the original stuff by putting a series of cuts, slices etc. in it which will allow it to breath underneath the new R-13, then to re-install the new fiberglass on top of it again and follow with a visquene vapor barrier on top of that and the 2x4 stud wall just under the sheetrock to replace the vapor barrier that I destroyed.
After letting everything dry out fairly well and making several (many many many) cuts in the vinyl on those two walls as recommended, I put the fiberglass bats in the wall again and made a test run on one wall WITH visquene over the top.
On the other wall, and after the cuts etc. were done as well, I put the glass insul. over it but -without-the visquene.
The next norning I pulled some of the R-13 insul. off of the wall with no visquene and the vinyl was covered with heavy moisture once again, the cuts made no difference. I cut a section of visquene open on the other wall and that area seemed to be dry.
I'm "assuming" the, "no visquene" wall was wet again because it now had no vapor barrier of any kind on it??
I will obviously cover both walls w/the visquene to replace the destroyed vapor barrier before I start with the sheetrock again but I'm hoping to get some opinions or any other ideas about the way I'm doing this before I start the sheetrock again.
Thanks... and I apologize for the length of this.
DW
I'm finishing up a 12x16' room inside the shop. The room is in one corner so two of the room walls are on outside walls.
I'm adding additional R-13 insulation to the outside walls and I've also put it in the inside walls along with R-30 in the cieling. Both the R13 and 30 have NO vapor backing, just plain fiberglass bats.
After installing the R-13 in the outside walls and (luckily) after only 2 pcs. of sheetrock were on those walls, I noticed a heavy amount of condensation on the vinyl backing of the original insulation, underneath the new R-13 fiberglass I'd added.
Talking to a few local insulation people, a couple of them had no clue as to why I'm getting the moisture. One person that seemed very knoledgeable told me that I need to destroy the vinyl on the original stuff by putting a series of cuts, slices etc. in it which will allow it to breath underneath the new R-13, then to re-install the new fiberglass on top of it again and follow with a visquene vapor barrier on top of that and the 2x4 stud wall just under the sheetrock to replace the vapor barrier that I destroyed.
After letting everything dry out fairly well and making several (many many many) cuts in the vinyl on those two walls as recommended, I put the fiberglass bats in the wall again and made a test run on one wall WITH visquene over the top.
On the other wall, and after the cuts etc. were done as well, I put the glass insul. over it but -without-the visquene.
The next norning I pulled some of the R-13 insul. off of the wall with no visquene and the vinyl was covered with heavy moisture once again, the cuts made no difference. I cut a section of visquene open on the other wall and that area seemed to be dry.
I'm "assuming" the, "no visquene" wall was wet again because it now had no vapor barrier of any kind on it??
I will obviously cover both walls w/the visquene to replace the destroyed vapor barrier before I start with the sheetrock again but I'm hoping to get some opinions or any other ideas about the way I'm doing this before I start the sheetrock again.
Thanks... and I apologize for the length of this.
DW