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I need to cover what was originally an exterior brick wall covered with plaster (brown & finish coat)with 3/8 drywall.
Any opinions as to whether it is better to attach the drywall directly to the plaster using masonry anchors vs. attaching to firing strips on the wall? I don’t need to run wiring behind the drywall. I was concerned about moisture from the brick & mortar transferring to drywall directly attached. Thanks!
Brent
Look closely at these common locations for hazardous materials in older homes.
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Replies
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I would drape the wall with a poly vapor barrier, and furr the wall 16" oc with concrete nails into the mortar joints, try 8d or 6d galv. first and see if they give a good grip. Another good nail for furring to brick is an old fashioned cut nail.
When you hang your rock, change to a 1" sheetrock screw instead of an 1 1/4" , that way, if you overdrive, the screw won't back the furring off the wall.
*Mike - wouldn't that be askin' for trouble? Seems like water would form on the vapor barrier and rot the furring. Not? This might be a good place for metal furring, maybe hat chanel.
*I lived for a while in a 70s era CBS (concrete block on slab) house in the Miami area. The inside was plaster over rock lath (dry wall with holes) on 1" x 2" nominal PT furring. No vapor barrier. Common construction in that area. Don't think I would use 3/8" dry wall over furring. 1/2" will give a better result. If this (as indicated) an interior (both sides) wall then a vapor barrier would not serve any purpose.
*Well.......if it is an interior wall then you're right , no purpose.But , I read that intro. and think that it is an exterior wall and the phrase "what was originally an exterior wall with plaster " means that it still is but that the plaster is falling off, or been removed and now he's trying to cover it with a new finish.So, I make the assumption that more moisture is comming from the outside - to - in (thru the brick and mortar ) and apparently Brent is too, so the vapor barrier stops the moisture from penetrating the furring and soaking the back of the drywall. This moisture may be what ruined the original plaster, but I'm just reading between the lines.How about it , Brent, anymore description of what existing and previous conditions are ?
*Sorry, I should have been more specific. The wall in question was the original exterior wall. In the late 20's an addition was built so it is now an interior wall. I don't need a vapor barrier on this wall. However, I am concerned about whether I can directly attach dry wall to the plaster. I thought moisture from the plaster might leetch into the drywall. I'm also attempting to save on buying furring strips, extra wall anchors, etc., etc.Thanks.Brent
*Brent: Ok delete the vapor barrier..............unless the old exterior wall is wicking moisture up from the footing.Tape a piece of poly to the base of the brick wall and cover it with a rug or something. Come back the next day and see if moisture has condensed on the back. If it has , include the vapor barrier. The old plaster will not add or detract from the moisture problem if there is no source of moisture.
*I have wondered about the same type of issue. This may raise more questions than answers. For dry (proven) interior masonry walls could you just glue the drywall to the plaster/brick/block with some sort of construction adhesive. On exterior block walls could you glue sheets of foam insulation to the block with construction adhesive and then glue drywall to the foam. (of course running electrical would not be possible). I was thinking of doing this in a cold room in the basement that will be used for storage. I don't know if this would work or if it is even feasable.
*Brent, Tim's way will work great. It has been approved for use like this in all of the interior spaces up here at Jons Hopkins Hospital Complexes in Baltimore. The exterior walls we had to use PT 2x4's flatt studded for furring and then we used rock with a foil moister vapor barrier applied to the back. The studs had a double sided foil tape to span the joints. This was using 5/8" rock for fire code but I later used 3/8" in my home. to fasten it we first scraped out any loose plaster and filled the voids,just for backing, with 20 minute mud (high adhesive properties for the exposed plaster as well as time) and trowelled it smooth. Next spead the drywall adhesive in 3/8" beads and press pull and press again to the wall. This ensures good contact and no waves from built up glue. Fasten with the Round case hardened masonary nails that are long enough to penetrate to block.Two notes as a side bar: 1. A lead abatement contractor applied an aproved sealer overthe walls at the hospital, always good to be safe in questionable situations. 2. Electric can be cut into the plaster/block prior to rocking them in. In Hopkins ALL electric is in E.M.T. period and shallow boxes work well. The E.M.T. can be tracked to the Main and wire snaked thru. Call an electrician familiar wih your areas codes.Good Luck.Mike, good idea about the plastic, I have used that to collect drinkng water durring S.F. Schoo.