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joewho
Premium
join:2004-08-20
Dundee, IL
Reviews:
·Comcast

plaster over drywall

Would anyone know of a reason to put plaster/metal lath other drywall? It's a 50 yr. old house, cinder block. In everywall I"ve opened up so far, there is 3/8" old drywall with 1/2" plaster on top. In the bathroom, there is drywall, plaster and another layer of drywall. I don't know when backed drywall was invented, and I'm wondering why I can't just tear out the plaster. Is there some support issue?
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Energystream
Premium
join:2010-04-16
Ridgewood, NY

Do you have a lot of curves or rounded wall details? Easier to deal with in plaster.

Otherwise they may have done it for greater fire resistance.



Corehhi

join:2002-01-28
Bluffton, SC
Reviews:
·Hargray Cable
reply to joewho

I lived in a house with textured walls and ceiling, drywall with plaster over top all the way around. I think it was just for decoration or to make it look like old time lathe and plaster.

I don't see a reason why the plaster can't be torn out.



Pacrat
Old and Cranky
Premium,MVM
join:2001-03-10
Cortland, OH
kudos:2
Reviews:
·Time Warner Cable
reply to joewho

Are you sure it's drywall? There's a plastering technique that involves "stapling" the mesh "lath" to a gypsum backer board before actually plastering. It's a more modern way to plaster than using wooden lath slats to plaster over. There's also a method where they apply a bonding agent to the backer board and plaster over that. I had an old ceiling replastered in an old house I used to own, and had the 9 foot ceiling coved. That was the technique the plasterer used to cover the flat part of the ceiling. He built the cove in the corners up using wire "lath" (looked like a light-weight expanded metal.

I don't think you can remove just the plaster coating if it was applied using any kind of bonding agent. I know the bonding material was very expensive... and it stunk to high heaven until it dried. The plasterer told me that using that material, he could plaster over glass and it would stick forever. Structurally, I don't think it's a big deal, but I suspect you'll have to strip it down to the bare studs and re-install new backer board/lath before it's all over. I doubt very much you'll be able to successfully separate just the plaster and leave the backer board.
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Keep your eye on the ball, your shoulder to the wheel, your nose to the grindstone, and your ear to the ground. Now, try to work in that position!!!


zach3
Zach
Premium
join:2000-05-04
Saint Louis, MO
reply to joewho

I had an Uncle that back in the 50's used 2 layers of Sheet Rock 1/2" thick, overlapped the joints and then finished off with a 1/2' of Plaster. His walls were 2x6 studs with full Fiberglass insulation. All done on a brick house. I was only about 10 years old but I remember he and my Father discussing the reason and it was for sound control and reducing the cost of heating and A/C. Yes full house A/C which at the time in the Midwest was not commonplace.



nunya
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
·surpasshosting
reply to joewho

It's a common method in older houses. After wood lathe fell out of favor, they used a product similar to drywall called "rock lath". I've owned several houses from the 1940's - 50's that used rock lathe.
It's just an ancient version of modern blueboard.
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If someone refers to herself / himself as a "guru", they probably aren't.


MaynardKrebs
Heave Steve, for the good of the country
Premium
join:2009-06-17
kudos:4
reply to joewho

Nothing like the feel and hardness of a real plaster wall (either over wood/metal lath or gypsum board). Sound transmission through the walls is also much less due to the higher mass and use of multiple materials attenuating the sound waves at different frequencies.

USG has a drywall board specially designed as a plaster substrate.


dmagerl
Premium
join:2007-08-06
Woodstock, IL
reply to joewho

+1 to what nunya said.

My house has rock lath and plaster. The rock lath comes in 16" x 4' sections. It's like they didnt know how to make full sized panels back then.

Total thickness of the rock lath and plaster is around 3/4" which makes for a much quieter room. Of course if you have to patch it and match thickness, it's a real bitch.


joewho
Premium
join:2004-08-20
Dundee, IL
Reviews:
·Comcast
reply to joewho

Click for full size
sample
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Here's a pic, drywall on top. I suspect it's what nunya said. Just glad no one said the "A" word.

To patch, I used 3/8 with 1/2 on top. Hate working with the stuff. Hard to cut a straight line and can't use regular drywall tools. pita.


Pacrat
Old and Cranky
Premium,MVM
join:2001-03-10
Cortland, OH
kudos:2
Reviews:
·Time Warner Cable
reply to dmagerl

said by dmagerl:

It's like they didnt know how to make full sized panels back then.

Not knowing how has nothing to do with it. Providing manageable sized pieces (for one person to install) is what it's all about.
--
Keep your eye on the ball, your shoulder to the wheel, your nose to the grindstone, and your ear to the ground. Now, try to work in that position!!!


jap
Premium
join:2003-08-10
038xx

1 edit
reply to joewho

Rock lath is still in production and a great product. Ones I worked with (Seattle, 2002) were 5/8" thick and can't recall sheet dimension but guessing 24"x32. Tremendous sound dampening and thermal sink.

Here in New England it's common to hang 1/2 or 5/8" gypsum (pre-treated with a plaster-bonding agent and referred to as blueboard) skim with two thin layers of plaster. A good supply of ace mud slingers in these parts.

said by joewho:

Would anyone know of a reason to put plaster/metal lath other drywall?

Out of curiosity, where did the metal lath fit in?

dmagerl
Premium
join:2007-08-06
Woodstock, IL
reply to joewho

In my house metal lath is used in all the corners, around windows, doors, etc. I guess its used to reinforce where cracks commonly occur. I didnt help. Cracks still formed as the house settled over the years.


joewho
Premium
join:2004-08-20
Dundee, IL

You know, I didn't really open up enough to see where it is. I'm sure it isn't over the whole wall because I cut some holes with no problem, I bet it's like you said. We have no current cracks.