Ancestor to Sheet Rock

[Will Crosby]

Hi there,
Does anyone know what the stuff is you sometimes see walls made of, in rooms I would guess were built or altered in the 1950's? There's a 1/2 - 3/4" thick outer layer, adhered to a second layer of similar thickness, with evenly spaced, round perforations. A cement looking product seems to have dripped through the perforations in the second layer, to hold the first one to it. It's hard to know what the size of the components of the outer product would have been. But from the back, the second (perforated) layer, looks to have been attached to the studs, in strips of 18 - 20" in height, running horizontally. I'd be grateful for any data anyone could share. Thank you.
Best,
Will

[Matt Day]

Rock Lath?

[Rich Enders]

Will,

We remodeled a home built in the 1920's which was originally done in lath and plaster. Wherever sections of the wall had to be replaced they nailed up "button board" and then applied plaster. The button board was about the thickness of the lath and had holes punched in for the brown coat to squeeze through and provide a mechanical hold. Plaster was then applied to the brown coat. That was in the 1980's and at the time in the Los Angeles area there were very few sub's that would still do plaster. It was more expensive than dry wall, but the sound deadening was excellent.

[George Bokros]

Originally plaster was applied over wood lath strips. Later rock lath was used. Rock lath did not have gaps left between the pieces as wood lath did.

[Will Crosby]

Button Board! That's it!! Any idea whether this was known to contain Asbestos or anything else scary like that? Thank you!!

[Rich Enders]

Will,

Button Board (Rock Lath) is gypsum in sheet form covered with paper or cardboard. Wikipedia does not mention any hazardous or toxic issues with gypsum.

[Stephen Musial]

Buttonboard (Rock Lath was a trade name kind of like Kleenex) was, as far as I know, always a gypsum product and I never heard of it containing asbestos. The plaster covering the board however is a different story. Up until the 80's, both joint compound and plaster may have contained asbestos. Even if you have old horsehair plaster, there's a chance that the finish coat could have asbestos in it. The only way to know for sure is to have it tested.

[Brian Elfert]

Buttonboard (Rock Lath was a trade name kind of like Kleenex) was, as far as I know, always a gypsum product and I never heard of it containing asbestos. The plaster covering the board however is a different story. Up until the 80's, both joint compound and plaster may have contained asbestos. Even if you have old horsehair plaster, there's a chance that the finish coat could have asbestos in it. The only way to know for sure is to have it tested.

How likely would it be that a house built starting in late 1979 would still have Asbestos joint compound or ceiling texture? Manufacturing of joint compound with asbestos was banned in 1977, but there was no ban on using up what was already manufactured prior to the ban. I plan to remove a whole bunch of drywall ceiling as part of remodeling the house.

Part of the reason I choose this house was that I figured a house completed in early 1980 would not have asbestos or lead paint to worry about.

[Stephen Musial]

Is it popcorn ceiling? I hear that it almost contains asbestos. Don't know how true that is but that's what I've hear from multiple sources. The joint compound may or may not. The tests are only about 30 bucks so look online and it will tell you how to safely take a sample and send it in. You'll want to take a sample from a joint so you get as thick a sample as possible.

[Chris Padilla]

My house was built in the early to mid 70s and my popcorn ceilings tested positive for asbestos. I've had most of them scraped by now but there are two bedrooms left with it still on the ceiling. Testing is cheap.

[Brian Elfert]

I suppose I should get the ceilings tested, but I don't know if I would have enough money for my renovations if I have to spend a bunch to get the drywall ceilings torn out. (The basement ceilings have to come out for the new duct work.)

[Stephen Musial]

What are you doing? Are the ceilings going to stay in place? If they're going to be staying in place, you could always just put another layer of 1/2" over the old ceilings and encapsulate the asbestos (if it tested positive) in place.

[Brian Elfert]

What are you doing? Are the ceilings going to stay in place? If they're going to be staying in place, you could always just put another layer of 1/2" over the old ceilings and encapsulate the asbestos (if it tested positive) in place.

Basement drywall ceilings are being removed to install duct work for a forced air system. I decided just to remove the entire ceiling since it will be just as easy to put up all new drywall than to patch. I also don't know exactly where the ducts will run. (House currently has electric baseboard heat that is expensive to run.)