I have a 1950’s Ranch House and I’ve been in the process of re-building it. Anyhoo…
I’m doing new construction windows and siding this summer, and I noticed that the
drywall is ~1″ thick and ordinary reciprocating saw blades just can’t touch the stuff.
An old-timer next door, tells me that I have plaster walls, with rock-lathe behind it as
a backer. From the attic, it looks like 16″ wide strips of drywall, thus the reason I
thought it was an early form of drywall. Anyone ever deal with this stuff? My
extension jambs windup short of the finished wall.
Thanks,
D
Replies
The good news is that you can often get it off in pretty big pieces, once you can get behind it to work.
Yep, you'll need wider jambs, and you'll use up a LOT of blades cutting it. I try to keep a supply of almost-worn-out sawzall blades for the times when I have to demo rocklath.
yes... it replaced wood lath... until drywall came along
my parent's house ( circa 1927) was built with rock -lath
very nice construction....
the process as i know it was ...
rock lath
brown coat plaster
finish coat plaster
My parents had their farmhouse rebuilt with the stuff ca 1966.
What is wanted is not the will to believe, but the will to find out, which is the exact opposite. --Bertrand Russell
Pretty common stuff back then. And it is a backer for wet trowlled plaster.
Have fun..(G)
Spheramid Enterprises Architectural Woodworks
Rock lath, not rock-lathe. Lathe is a machine for turning.
shhhhh...
Yep... realized I put an "e" on the end. oops.
What , you've never worked on a rock lathe?!!
Stone turning is an ancient albeit little known trade. I have a beautiful sandstone vase out front, and a granite pepper mill I just used this morning.
The slate salad bowls were fairly difficult, but they season up nicely.
I've turned soapstone, and talc. They're pretty easy to work, easier than some of the exotics.
Never really turned any stone. Saw some guys doing alabaster once, quite beautiful.
Oh yeah.
I've turned alabaster, too. That's a little harder than the others, but still not bad.
Only here at BT can a topic go from rock lath to tuning rock on a lath, and it's considered par for the course. Speaking of which, I listen to rock. --------------------------------------------------------
Cheap Tools at MyToolbox.netSee some of my work at AWorkOfWood.com
Actually, it should be " from rock lath to turning rock on a lathE " LOL
but you're right. There's no telling where a thread might go here.
Back when I first started remodeling, this was what was used for lath for plastering. Bull nose edges, 1/2" thick, nailed up. As another poster said, you put down a scratch coat (or two, depending) and then a finish coat. Never taped any seams or corners on this stuff, but I guess the plaster was thick enough that it wasn't needed.
Sounds like you need wider extensions.
Mike Hennessy
Pittsburgh, PA
It was used on my parents' house in the 60s because it was an old farmhouse with uneven walls. Drywall would have looked a fright.
I guess now they just drywall and then pour on the mud.
What is wanted is not the will to believe, but the will to find out, which is the exact opposite. --Bertrand Russell
"I guess now they just drywall and then pour on the mud."
Only if they're hacks who never heard of shimming! ;-)
I still do a bit of plastering now and again. Makes me remember how much I hate it! LOL.
Mike Hennessy
Most installations of this around here have expanded metal lath at inside corners and at wall to ceiling joints.
Is there anything better to demo than expanded metal lath? Thats stuff "blood lets me" on every job.
I wonder if it was as much fun installing as it is taking down?
Here in Chicago I run into rock lath quite a bit, pretty much anything built between 1930's to early 1960's. Some workers I know use a diamond blade on their 4-1/2" angle grinder to cut it into sections, but that creates a serious dust cloud. I prefer to use a 6 point blade in my reciprocating saw - slower but a lot less dust kicked into the air.--------------------------------------------------------
Cheap Tools at MyToolbox.netSee some of my work at AWorkOfWood.com
Thanks. I've actually been using a carbide grit sabre-saw blade with good success.
Went through tile, and the rock lath all in one shot. Prior to that, I was swapping
blades out like chiclets.
-D
I hear ya. What's even more fun is to demo diamond lath that's been scratched coated and browned out with portland. They often did that in the bathrooms of the higher end homes I've worked on. On the first whacks the 9 lb sledge just bounces off, and I know it's going to be a long day.Time to call in the young monkeys with the strong backs and weak minds.
We did a bathroom demo once where all the walls were made of metal lath (and plaster) and the floor pour was 4" thick.
32 sqft bath took 1.5 days to demo.
I had one like that years ago, when I was working for my dad.
We started demo-ing the shower stall, but the sledge hammer just bounced off the walls, barely leaving a mark. We had to rent a chipping hammer.
It turned out the shower walls were about 3-4" thick concrete. I always wondered if the original owner planned on using it as a bomb shelter.
About reinforcement:I have rock lath on my 40s house that went down the road 35 miles until it got to my property - most walls were fine, a few hairline cracks on the ceiling. <g> However, all the corners, inside and out, and around the doorways were reinforced with diamond lath, and there was chicken wire all over the ceilings to boot. I only took down the kitchen ceiling because i don't have soffits now, but i'm never ever gonna think about taking down any more...that took f-o-r-e-v-e-r.
I think rock lath walls are the best of both worlds- nice plaster walls, without all the wood lath problems. I see a lot less cracks with rock lath than I do with wood.
The current equivalent would be plaster over blue board. But rock lath has a brown coat over the lath. Blue board requires just a skim coat of finish plaster.
We called it button board in Calif. Must be a regional thing. the metal lath at corners always makes for a real fun demo.John
up until about 5 years ago, it still came 16"x 48" with 6 pieces in a bundle (32 sf) the pieces were held together with wire
then it switched to 24" x 96" with 2 pieces per and they were bundled with standard drywall paper at the end.
our plaster told me last month that they can't get that anymore and that he is claiming that rock lath is basically dead as a product.
he is now browning and finishing over regular drywall.
carpenter in transition
Interesting point about rock lath: You ain't never seen anyone work as fast as good rock lathers. They work with a hatchet and do all the cutting with that -- score and whack for a straight cut, or chop to make an outlet opening. Since the walls will be plastered they don't need to worry much about fit, so they can really bang the stuff up. Floor's a mess when they're done, though.
What is wanted is not the will to believe, but the will to find out, which is the exact opposite. --Bertrand Russell
about 80% of Pittsburgh is built with rock lath.
the other 80% or so is other stuff.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
Its pretty common. I figure it went like this. First there was lath. Can you imagine what a job it was to install lath throughout a house? Then they came up with the gypsum product you have. Things went much quicker. Then finally 4x sheets of gypsum. At this point I picture these guys slapping their foreheads and saying, "why not just patch the joints? We'll save hours from our job.".
I could be wrong but I always picture it that way.:>)
Like the rest of the posts say, rock lath is actually a very common product that was used in the homes built in the 1920's through the 1960's.
I plastered onto it back in the mid 70's when I was first getting into the trades and they still sold it. Some was made with perforation holes in it to key in the scratch coat.
The house I'm renovating now has a type of lath I've only seen a few other times. It's a fiberboard not unlike homosote that was used the same way as rock lath with the two coats of plaster on top. It was terrible stuff because through the years it moves and the plaster cracks and shows the dimensions of the pieces installed. Looks like they came in 16" x 48" pieces.
It was made for plastering because on the back is the USG label and it says plaster lath on it.
Things change....thank God.
If you can find them, try useing the carbide grit sawzall blades. They will last a little longer. Or you can use a masonary wheel in an angle grinder ( but that gets a little messy).