# Post Plaster/Pre Drywall



## Tech Dawg (Dec 13, 2010)

I'm starting this thread for a moderator that didn't want to ruin his post reputation :whistling::laughing: but it does seem a bit interesting to me as well...
At some point in the 50's/60's, walls were constructed of 2ft gypsum boards and some coat of hard plaster over top... are any of you drywallers old enough to have done this process?? Just wanted to learn a little about it and if there was any kind of science behind it...


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## griz (Nov 26, 2009)

Never did it. I do remember as a kid, about 1959, (no snickering) seeing it being done on a house in the hood. Seems to me the wall boards were perforated on 2" centers or so. Didn't have any use for it in the tree fort so we left the scraps.


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## Tinstaafl (Jan 6, 2008)

Oh, thdpthdpthdp! Go to bed, Todd.

Todd and I were talking about how that stuff has a surface that will destroy a multimaster blade in about 12", and neither of us had a clue as to what it's made of, or the finishing process. When you look at a cross-section, it appears to consist of two layers. The lower one is softer, but the surface is rock-hard.

What was it called, and what other trivia does anyone know about it?


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## Tech Dawg (Dec 13, 2010)

Tinstaafl said:


> Oh, thdpthdpthdp! Go to bed, Todd.
> 
> Todd and I were talking about how that stuff has a surface that will destroy a multimaster blade in about 12", and neither of us had a clue as to what it's made of, or the finishing process. When you look at a cross-section, it appears to consist of two layers. The lower one is softer, but the surface is rock-hard.
> 
> What was it called, and what other trivia does anyone know about it?


:laughing: cmon Tin... I thought you coulda rode this out a little longer without saying anything :lol:


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## Tech Dawg (Dec 13, 2010)

Actually, I think that I always subconsiously wondered if there was a name for this or any other detailed info or if it was just 2 year fashion in the business...


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## Big Shoe (Jun 16, 2008)

I've seen that stuff. I think they also used that system in schools here. Thought they called it ''lath board'' or ''rock lath'' and plaster.

That almost seems like stuccobut smoother. We need an old time plasterer.


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## Frankawitz (Jun 17, 2006)

It's called Plaster, the board is rock lath they are 4' x 16" x 3/8" these boards are installed by lathers, they would install in a brick pattern laying rock lath on a starter strip of 1 x 2. then they would could the corners and seams and butt joints with diamond wire mesh. then they would mix up Portland Cement, Sand, lime, and horse hair somethimes. this was troweled over rock lath, then Plaster was applied over that, they would trowel it to a smooth finish. They would use a mop brush to wet down plaster then they would burnish it.


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## tkrrox (May 15, 2010)

i always called it button board, and the closest i've seen to the plaster finish now is california one kote and i put it over blue board


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## Tinstaafl (Jan 6, 2008)

Frankawitz said:


> It's called Plaster, the board is rock lath


Sounds like you've nailed it. So this would be the crossover between the true old time lath/plaster and today's drywall? I'll have to look more closely next time I run across it; I've always thought there were only two layers.

Certainly explains why the stuff is so hard on cutting tools. :laughing:


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## angus242 (Oct 20, 2007)

It has been in almost every home I have worked in that was built pre '84-ish.

Although the rock lath I see is 2'x8'.


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## loneframer (Feb 13, 2009)

My parents home was built in 1950 and it's done in Rock lath and plaster. Actually the whole neighborhood was. No horsehair though. Probably loaded with Asbestos though.:whistling


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## angus242 (Oct 20, 2007)

Tinstaafl said:


> Certainly explains why the stuff is so hard on cutting tools. :laughing:


This is the best blade I've tried with the stuff:
http://www.amazon.com/Milwaukee-48-00-1420-Carbide-Sawzall-Masonry/dp/B002AYDESO


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## Sir Mixalot (Jan 6, 2008)

My dad told me that they would have a whole dump truck load of sand delivered to a new home that was to be plastered and they would use all of it in the plastering process. I have an old book that has a whole section on the plastering procees. This is a book from 1962 that was one of my Dad's that he left to me. It's a very informative book with a lot of details. Probably one of the first "Do it yourself guides". It has over 1500 pages on everything from Plaster, drywall, roofing to kitchen cabinet blueprints.
Here's a couple Pictures of the book. When I have more time I'll try and and get closer up in the pictures and I'll type out all of the text from the pages in the plastering section of the book.:thumbup:


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## Tech Dawg (Dec 13, 2010)

angus242 said:


> It has been in almost every home I have worked in that was built pre '84-ish.
> 
> Although the rock lath I see is 2'x8'.


Yes, this is what Tin and I are talkin about.... 2' rock and plaster over top... (no wire lathe or horsehair) just 2 layers...


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## angus242 (Oct 20, 2007)

Tech Dawg said:


> Yes, this is what Tin and I are talkin about.... 2' rock and plaster over top... (no wire lathe or horsehair) just 2 layers...


See it often...er, _SAW _it often...pre-RRP :sad:


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## Tinstaafl (Jan 6, 2008)

Sir Mixalot said:


> When I have more time I'll try and and get closer up in the pictures and I'll type out all of the text from the pages in the plastering section of the book.:thumbup:


For your sake, I hope you never wind up with that much time on your hands. :laughing:

But seriously, if that's something you really want to do, a scanner and any of many readily available OCR applications would chop the work involved way, way down. Just make sure you're okay copyright-wise. :thumbsup:


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## Big Shoe (Jun 16, 2008)

I tangled with some of that stuff up in the Chicago area before I moved to Florida in 79. Most of the homes in my hometown were plaster. 

I've often thought to myself ''I'm wonder how much fun I'd be having if I was still up North tearing out all those plaster walls''.:sad:

I would guess I've messed with a handfull of houses here in Florida that had plaster walls.

As far as I know there is only 1 company in our area capable of doing a professional job. They are the guys that keep busy in Tiger Woods neighborhood. They are also very expensive.

As far as cutting, I would say angle grinder/vac or hatchet for a straight line.


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## rogerhattman (Jul 6, 2008)

Here in my neck of the woods (the NE), when wood lath fell out of favor (1930s), the lath of choice was rock lath, which was basically 3/8 drywall with a heavy duty facing to handle the extra water from the plaster. It was laid on as Frankawitz says and covered with a brown coat. Sometimes you see cornerite (metal lath on inside corners) and other pieces of striplath to reinforce, but mostly I do not. This was brown coated (sometimes a scratch coat was used, but this was rare in my experience) with a job mixed sand aggregated plaster. In about the 1950s or so, this was replaced with factory mixed lightweight aggregated factory mixed plaster (eg Structolite or Gypsolite). Finish was usually gauging plaster and lime. Occasionally keanes cement was used over sanded basecoats. In the case of a lightweight aggregated browncoat, an aggregated finish coat is required, which is usually perlite fines. 
I find that a rotozip with tile bit cuts ok with minimal collateral damage, though it is messy. I hold my vac end where I cut.


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## jkfox624 (Jun 20, 2009)

The metal in the corner makes for a bleeding mess when trying to tear it out. The rock lath is alot easier to tear out though, once you get a hole in you can peel the 4 foot chunks out which is nice, because its about all one person wants to carry out by themselves if doing it all day.


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## Tinstaafl (Jan 6, 2008)

rogerhattman said:


> I find that a rotozip with tile bit cuts ok with minimal collateral damage, though it is messy. I hold my vac end where I cut.


I'll have to try that. Though Rotozips are messy by nature, I have a vacuum attachment for mine that makes it pretty livable.

Thanks for the history lesson. :thumbsup:


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