Replies

1. 
   Gabe_Martel | Dec 07, 2001 03:27am | #1

   *
   Kim,

   You've got a commercial building, 12" masonry walls, coated with bit. membrane. You don't need the 6mil poly behind the wall. The metal studs are fine with the insulation and the gap is okay. Install the poly on the warm side and cover with sheating. Use accoustic caulking on the underside of the tracks, and between the plastic and the tracks.

   What you want to do is PREVENT the warm moisture laden air from inside the building (assuming that it's heated) getting between your masonry and sheating. If it does is will condensate on the masonry wall and cause you grief.

   Gabe

1. 
   Tim_Kline | Dec 07, 2001 03:41pm | #2

   *Gabe, The poly was already hung over the block when we studded the walls. I don't think that by itself the poly over the block is going to cause a problem. (Do you agree ?) I think that you are correct that the interior conditioned air coming in contact with the cool block is where the trouble is. Unfortunately, this is a 24" on center bar joist and metal deck job. We just finished topping out the drywall to the deck in the corridors (one hour, thank God) and I am trying to imagine doing another 300 lineal feet of this in an attempt to make the exterior walls airtight. The plan calls for just running the drywall above drop ceiling line and not up to the deck on these walls.

1. 
   Jeff_Clarke_ | Dec 07, 2001 07:18pm | #3

   *i The plan calls for just running the drywall above drop ceiling line and not up to the deck on these walls. If that's the case, Tim, you might want to consult the building department or architect (if any), since exposed flammable vapor retarder(s) and/or poly above the wallboard line (and above the ceiling) may cause you construction code problems, depending on your applicable code.Jeff

1. 
   Gabe_Martel | Dec 07, 2001 11:50pm | #4

   *Tim,The poly won't do anything detrimental to the system but it won't add a pinch of coon shit either. It's absolutely useless behind the wall studs.It's good that you're running the drywall to the deck and I assume that the roof is insulated over the deck. Should be fine.Gabe

2. 
   Tim_Kline | Dec 07, 2001 11:50pm | #5

   *
   Southeast Pennsylvania
   Commercial building, 12" uninsulated block walls coated with bituthene membrane waterproofing. Full footer drainage system with separate roof drainage system. Interior of block is covered with 6 mil poly. 3 5/8 metal stud walls are 1/2" from block. Insulation contractor recommends unfaced R-13 fiberglass. Have requested manufacturer's recommendations on this. Any thoughts here on faced or unfaced insulation ?