New wall meeting an old one


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Old 08-28-03, 03:17 AM
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New wall meeting an old one

Hi:

I'm building a new wall that will intersect an original wall. The new one is drywall, the old is plaster and painted. Do I need to prep the old wall in any way so the tape and mud stick well at the corner seam?

Thanks.
 
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Old 08-28-03, 03:48 AM
mudder
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scuffing the the painted wall at corner with sandpaper removing any gloss will help. you might also concider if the new drywall fits tightly against the old wall just running a bead of high quality latex caulking in the corner and smothing with finger instead of taping.
 
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Old 08-28-03, 10:41 AM
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In all the commercial work I design, I always call for sheetrock that abuts a dissimilar material to be terminated with a mud-in type casing bead. When I say "mud-in", what I'm talking about is a piece of metal trim that covers the edge of the sheetrock with a perforated flange that looks a lot like a corner bead; the face of the casing bead is designed to be covered with joint compound just like a corner bead.

That casing bead is held away from the plaster and the joint is caulked with a paintable caulk. If you tape the joint between the sheetrock and plaster, I can almost gaurantee it will crack.

Bruce
 
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Old 08-28-03, 11:58 AM
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Why will it crack? If your drywall isn't tight to the wall, make sure you pre fill with mud. Then run your tape as normal and finish. If it does crack then run caulk. This isn't a commercial job.
 
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Old 08-29-03, 02:40 AM
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You certainly can tape it in and wait and see if it cracks; maybe it won't. But we saw enough of it over the years that the casing bead detail has become our office standard; saves that call from our client and trying to decide who should pay for a repair.

I honestly don't know why it wants to crack but we see a lot of it, including on my own house when I couldn't convince the tapers to put in the casing beads like I wanted. I also was going against an old plaster wall. Drywall and joint compound don't seem to know if they're being installed in commercial or residential.

Bruce
 
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Old 08-29-03, 08:37 PM
bungalow jeff
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It will crack if one of the two walls has a bedroom door and a teenager to slam it.
 
 

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