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Removing old plaster lath wall

Posted by mickimax (My Page) on
Thu, Feb 2, 06 at 9:55

My brick, colonial style house was built in either 1868. I want to take down a couple of interior walls. I will work with a contractor to see about load-bearing issues. I opened up a small section of one of the walls, about 3 inches in diameter, just to see what was under there. The outer layer is a textured wallboard, sort of like drywall. This was probably installed 50 years ago. Under that wallboard, about 1" underneath, is the original plaster wall. Under that plaster, is the wood laths, which are about " apart, and contain plaster between them. I noticed a lot of hair (horse-hair?) in with the plaster. Is anyone familiar with this type of wall? Is this what one would call horse-hair plaster? Any suggestions for my removing this wall?


Follow-Up Postings:

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RE: Removing old plaster lath wall

Yes. Very common wall. Just about every house built prior to 1930 had that kind of wall construction.

Once you get the wall opened up in a couple of places, you can try scraping the plaster with an ice chopper. I've done that in the past to fairly good result.

Invest in a HIGH QUALITY respirator and a face shield. Don't rely on the filter media masks.


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RE: Removing old plaster lath wall

The horse hair was added to the plaster to make it resist cracking. Fiberglass is used today to accomplish the same purpose. Lath and plaster is not considered to be structural, but it does stiffen a wall and would help a structure stand up to high wind. Since you refer to an interior wall, I am guessing that there are wooden studs behind the lath & plaster.


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RE: Removing old plaster lath wall

Yes, there are wooden studs and square-head nails (iron?)After opening up the small section, I feel guilty about wanting to tear down the wall now, it is so painstakenly put up, and has been up for 150 years! But I want to open up the room to the hall! I feel like I'm disrespecting the original builders work. Sigh.


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RE: Removing old plaster lath wall

Easiest way I've found to demo plaster and lathe it to open up a section, then insert about half of a 36" or 48" pry bar down into the stud cavity. By pulling towards you, you can use leverage to pop the lathe and all the plaster attached to it right off the wall.

It tends to come off in large chunks which makes the job less dusty and disposal much easier.


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RE: Removing old plaster lath wall

In addition to protecting your lungs with a respirator, you'll want to seal off the entire area as air-tight as you can. Otherwise, the plaster dust will makes its way EVERYWHERE in your house. In fact it will do that despite your best efforts. But less is better.


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RE: Removing old plaster lath wall

Demo can be great fun :-) Definitely use a dust mask, some people say to mist the area to reduce the dust. People also warn that one should have the wall tested for asbestos before demo although I would welcome info on how/ where such a test is done.


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RE: Removing old plaster lath wall

He he, pd06, demo is fun?

Anyways, here's the info on home testing for asbestos. Seems to me it's like soil testing.

Ted

Here is a link that might be useful: asbestos testing


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RE: Removing old plaster lath wall

I would suggest to be careful about demoing a plaster wall near another section of plaster which you intend to keep. It may not be so much of a problem with a whole wall (both sides) coming down, but perhaps take caution near the corners.

DH and I remodeled a bathroom last summer, where we gutted the room down to the wall studs and basically built it up from scratch. We had to be careful about banging on the exposed side too much for fear of cracking or otherwise damaging the "good" side of plaster wall in the adjacent bedroom. Perhaps the "pros" on this site can tell you if I was just overly paranoid, but watching my husband pound away like John Henry when banging a nail or something into thre stud, and seeing the back of the other plaster wall shifting and the keys crumbling here and there, had me on edge like you would not believe.


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RE: Removing old plaster lath wall

Horsehair plaster the best! I'm surprised old house lovers didn't chime in here and say don't do it!!!

We are in a reno from flood - my husband cries with each crumble of plaster has wonderful acoustics, fire resistance, and maybe holds heat and cool longer -

I hate drywall we are in a rental while our house is being repaired - it's like being in a tin box!


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RE: Removing old plaster lath wall

We have that plaster in our house. It was built in the 1920s and the lathe here is yellow poplar with the horsehair cement-like (lots of sand) plaster over and between, lipping over each board. The hair holds it all together. Over that was a smoother plaster finish that was the wall we look at.

We have removed many of these walls; the pry bar is the tool we found mose helpful. A reciprocating saw took care of the lathe at the corners of the room. Lots of old wiring in these walls, so be on the lookout.

Have fun! These well-built homes are worth all the work you are willing to put into them. We have remodeled ours for 28 years, so far!


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RE: Removing old plaster lath wall

Is there anyway to remove the plaster without disturbing the wooded lath?


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RE: Removing old plaster lath wall

Certainly is, torontorenos. I use a "dead blow" hammer (less bounce than a steel hammer and easier on the wrists) to whack the hooked end of a wonderbar at a 45 degree angle to get started. You'll run into lath after a couple of blows, then just continue up and down the wall, just deep enough to expose the lath, leaving a furrow of exposed lath.

That's the hard part, getting it started. After you have a vertical furrow, start going horizontally along the lath with a flat bar - the plaster should just peel away once you get between it and the lath.

Of course as you break it, the plaster "keys" will fall into the wall cavity, but most of the plaster will be on the floor. The nice thing about knocking down the plaster separately is you have a pile of pure plaster rock, which is easy to handle with a flat shovel (compared to having miscellaneous lengths of lath mixed in).

You'll have a cool-looking wall of lath in no time! I'm not sure why you'd want it - it's not all that flat and of course you can see right through it. I don't even think it's fit for re-plastering because the lath is too dried out, though I've never actually tried it.

I've tried every method of plaster removal (sawing, smashing etc.) and I find the dead-blow/wonder bar method the most pleasant. You can also position a plastic mortar box under where your working to catch most of the plaster for easier cleanup.


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RE: Removing old plaster lath wall

Just popping in to say that you can indeed replaster over old lath--you just have to be sure to wet the lath so it doesn't suck all the moisture out of your new plaster wall and turn it to sand.


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Removing Slat & Plaster The Right Way

I've removed many slat and plaster walls and this is the most efficient\minimal mess technique I have discovered. The fact is, this is a messy job and "bashing walls" is out of the question if you want to minimize the spread of dust and cleanup time. Here's what you need and how to do it:

1. Quality respirator mask (no exceptions). I recommend a $19 dual filter mask from Wal Mart.
2. Thick durable work gloves.
3. Protective plastic goggles (Wal Mart).
4. 1 Large black marker.
5. 10 X 12 thin plastic drop sheets (Wal Mart).
6. 1 flat pry-bar.
7. 1 Drill with half 1/2 inch bit.
8. Reciprocating Saw (any reliable brand will do) with extension chord.
9. 1 stud finder.
10. 1 ladder.
11. Large 96 gallon square trash bin with wheels or durable plastic storage container with wheels (preferably).
12. 1 Shop vacuum.
13. 1 Broom & dustpan
14. A partner to help (needs items 1, 2, & 3).

Step 1) Turn off the power in the room that contains the wall you plan on stripping. You do not want to electrocute yourself! If other rooms have power receptacles on a separate fuse you can run an extension chord into the work room to power a flood lamp. Or if it's daylight you're all set ;)

Step 2) Remove all wood trim from wall. Using the ladder, stud finder, and the black marker, start about 5" down from the wall\ceiling crease and locate and mark all the wall studs on the wall you plan to strip plaster slats from. Make your stud marks horizontal and 4" wide. Have your partner mark where the stud finder began beeping and where it stopped. Make note of all electrical switches and outlets. If you have multiple plugin outlets on a single wall chances are the wiring will be horizontally ran inside the wall to join the outlets. Use the marker to draw a horizontal line between outlets. You will not cut below or within 5" of the top of this line.

Step 3) Cover the floor of the room where you're working with the 10 X 12 plastic. I like to "booth off" the room with plastic by taping 10 X 12 sheets from the ceiling to the floor using blue painters tape as it will not rip your drywall paint\paper when you remove the tape. I tape all joining plastic sheet seems from ceiling to floor and allow a slit for me to walk out during breaks.

Step 4) Put on you respirator, goggles and gloves. Make sure your respirator is tight enough not to let air in and the nose bridge is snug on the bridge of your nose. You do not want ancient dust creeping in your mask! A hat is optional if you don't want dust in your hair (ladies). Position the 96 gallon trash can by the ladder and have your partner waiting for you to hand them square slat and plaster section to put into the garbage can.

Step 5) Start at the left hand side of the wall. At the top of the ceiling, using the drill and the 1/2" bit, drill a hole on the right end of the 4" stud marking. Only drill a hole in the section your are currently working on.

Step 6) Place the blade of the reciprocating saw half way in the 1/2" hole you drilled earlier and begin sawing downward. gently add downward pressure to the saw, don't force the saw, let the saw do the work. It should cut through like butter. Keep your cut line as straight up-and-down as possible. You can also steer the saw close to the parallel wall stud for a closer cut. If the saw blade pops out or is hard to move, chances are you're cutting into a wall stud. Stop, evaluate the situation (using a flashlight), and reposition and continue to cut just the slats and plaster. Stop cutting when you're about 2" from the floor. You should now have a semi-straight vertical cut line from ceiling to floor.

Step 7) On the ladder, using the pry bar, at the top of the wall, you will pry off your first single square section of wall by using the following technique. At the top of the wall, from left to right, diagonally slide the pry bar (hook end towards you) behind the cut plaster panel and leave the very end of the pry bar(flat end) sticking out at the lower bottom left. With your right hand, firmly grad the upper right of the plaster section, holding the hook end of the pry bar against the back of the plaster wall section. With your left hand, firmly hold the flat end of the pry bar behind the lower left corner of the plaster wall section. Slowly pull the entire panel of plaster towards you keeping the pry bar firmly pressed behind the plaster section you are removing. If you do it correctly you will keep 98% of the plaster in tact and all nails joining the wood slats to the 2 X 4 beam will be pulled out at the same time. Hand the square plaster section to your partner to place in the bottom of the 96 gal plastic trash can. Continue this technique all the way down the cut in the section you are working. You should get the hang of it by the time you're done with the removal of your first section.

Step 8) Repeat steps 5 through 7 until the wall is stripped. You may have some remaining nails to remove with the pry bar when you are completely finished with the entire wall.

Step 10) Pick up stray pieces of plaster and slats when you're finished. Gently roll up the plastics sheets being careful not to spread the dust; dispose of the plastic. Sweep and vacuum and remaining dust and debre that escaped the plastic.

You may need to make several trips to the waste transfer station with the trash can to dispose of the slat and plaster or you can pay someone to pick it up. I have this technique down to where I can strip a 10 x 8 wall in 60 min with little or no mess on the floor. Have fun, be safe.


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RE: Removing old plaster lath wall

Oops, I skipped a step! Step 10 = step 9.


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RE: Removing old plaster lath wall

You can also blind start the recip saw into the plaster.
Buy a lot of blades, you are going to need them.

I actually make two cuts per stud bay as tight to the studs as possible without cutting into them.
A few horizontal cuts makes 'panels' than can be handled easily.

While the sawing releases some dust, it is far less than breaking the plaster up.


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RE: Removing old plaster lath wall

Hello! I've removed a couple of rooms of plaster in my house, and this is the system that I've worked out. You can read more in detail on my website if you'd like.

1. Remove everything in the room that is on top of the plaster (light fixtures, outlet covers, molding, thermostats, etc.
2. Starting at the bottom of the walls and working up, "spear" at the plaster with the wide edge of a sledgehammer. This will loosen up and drop the plaster and leave the lathe intact.
3. Shovel up and remove the bulk of the plaster.
4. Remove the lathe with a hammer and wrecking bar. You may have to bag old insulation as you go.
5. After the lathe is out, there will be some plaster that fell behind it. Shovel it out.
6. Sweep up the bulk of the dust with a push broom.
7. Give the entire room a good sweep with a Shop-Vac. Use a cartridge filter AND bag so your motor does give out like mine did the first time around!

Here is a link that might be useful: Best Way to Remove Plaster @ 98 Market St.


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RE: Removing old plaster lath wall

Three coat plaster was the standard wall for a long time.

The first coat had hair mixed in and some sand.
It was pressed firmly against the wood lath to extrude through the gaps and form 'keys' to anchor the plaster solidly. This was the scratch coat. Before it fully hardened was scratched with boards with nails to roughen up the surface slightly so the next coat would stick better.

The next coat had sand but no hair. It was used to start leveling off the surface and was called the 'brown coat.'
The sand is added to stretch the plaster.

The finish or putty coat was the final layer.
It was lime putty for many years, than a mixture of lime and gypsum plaster, and finally gypsum plaster with a LOT of retarder added to slow the hardening.

Lime putty hardens very slowly, making it easier to work with.
Adding some gypsum plaster increases the set rate.

Plaster walls are not sanded at any point in installation, they are worked smooth.

The final layer could have various things added to give differing textures, and be textured with brooms, brushes, etc.

The NPS Brief is pretty good.

Plastering Skills by Van Den Branden goes in and out of print and is a good reference if you want to try the old ways, or some of the adaptions to them.

Scratch coating is surprisingly hard work.
Finishing the putty coat takes practice to get a flat surface over large areas.

My old plaster friend died a few years ago.
He could do everything from walls to running molding and making and hand finishing decorative shapes.

Here is a link that might be useful: NPS Preservation Brief on Plaster


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RE: Removing old plaster lath wall

I am interesting in buying a house built 1920. I havn't seen any asbestos anywhere,but I was wondering if it could be in the walls .The walls look like plaster boards. If you can help I would be thankkful


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