# Drywall patch 1950's wall



## KingJames603 (Aug 18, 2016)

I have to make a drywall patch which the surface feels loose. When I opened a hole with the loose surface I noticed a backer board that I cant put a 1x2 furring strip behind due to that backerboard. I would have to make a patch about 3" x 8" between the studs. The wall and the backerboard is 1/2" depth. The first picture shows the hole in the wall and the second picture shows another wall in my house that has a view of what the backerboard panels look like. How would I fix this, with a 3/8 drywall patch adhered to the back with joint compound or glue, open a hole in the backerboard to screw in the furring strips, or some other method?


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## mark sr (Jun 13, 2017)

What is the backer board made of? drywall?


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## ClarenceBauer (Mar 4, 2005)

That is a rock Lath system.
You stated that there is only 1/2 inch space between the backs of the walls what you can do is put a bond breaker on the exposed sheathing you see behind the hole. Bond breaker can be something like wax paper or any other material that plaster will not bond to. than fill hole with say a base coat of a gypsum product. can even use a setting type compound for a small area.
If you have a large area use a Perlite Plaster.


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## ClarenceBauer (Mar 4, 2005)

If you are going to need to fill the lower area in photo # 2 use the Perlite Plaster direct to the exposed Rock Lath.


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## ClarenceBauer (Mar 4, 2005)

Skip the BOND BREAKER I was thinking that you had a space between two walls, just use Perlite plaster direct to the board.


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## siffleur (Aug 19, 2013)

KingJames603 said:


> I have to make a drywall patch which the surface feels loose. When I opened a hole with the loose surface I noticed a backer board that I cant put a 1x2 furring strip behind due to that backerboard. I would have to make a patch about 3" x 8" between the studs. The wall and the backerboard is 1/2" depth. The first picture shows the hole in the wall and the second picture shows another wall in my house that has a view of what the backerboard panels look like. How would I fix this, with a 3/8 drywall patch adhered to the back with joint compound or glue, open a hole in the backerboard to screw in the furring strips, or some other method?


KJ603, I am curious where that drywall screw came from in the first photo. That certainly is not from the 1950s.

Based on the size of the screw (almost full size) and the hole on my screen, and without see too much more cracking material other than that in the photo, I might do the following:

1. Remove all the loose and cracking materials, using a shop vac to catch whatever materials you are digging out so the they don't get in between the top layer and the backing material. THis is so you don't get an outward bow on the top surface.

2. If the surrounding top layer appears to stay flush against the backing layer, I would make a batch of USG Durabond 20 (easily available in many areas) with the consistency such that the mix will slowly drip off a large rubber spatula when turned upside down (I use a rubber cupped spatula and stainless steel mixing bowl to mix my USG Durabond and Easy Sand).

3. Using a 4-6" spackle knife I would push the Durabond into the hole and against the sides of the top layer material, taking care not to overfill the hole. Let this dry for several hours or overnight. The Durabond will stick like glue to everything it touches and dries on, basically making the top and backing layers one piece.

4. When the first batch of Durabond is dry, make a 2nd batch that is a little stiffer than the first. You want the Durabond stiff enough so that when you fill the rest of the hole it stays in place and does not run or bulge out of the hole. Use a spackle knife that is larger than the hole is. Again, make sure not to overfill the hole.

5. One more coat of Durabond should finish this nice and flat.

6. If the 2 layers of wall are not flush against each other before you start filling with Durabond, put drywall screws around the area to hold the top layer against whatever the backing is. You might have to counter-sink the screws so you don't crumble the material on top. The idea is to get the top layer of material to bond the 2 layers together, but not to get in between these 2 layers.

When I am doing prep work on a job and come across something like this I find that I can easily get it done the way I describe just by fitting it in with all the other little dings I am working on - a round robin sort of thing. That way I am not just sitting there and waiting for spackle to dry.

siffleur


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## Domo (Nov 9, 2018)

Come on guys and gals - this is 50's lath and plaster and it's not a restoration project.

Pull it off, remove the lath, true/shim the studs and hang new wallboard.

You're looking at 4 hours of work including cleanup to get the wall covered and ready for taping.


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## siffleur (Aug 19, 2013)

Domo said:


> Come on guys and gals - this is 50's lath and plaster and it's not a restoration project.
> 
> Pull it off, remove the lath, true/shim the studs and hang new wallboard.
> 
> You're looking at 4 hours of work including cleanup to get the wall covered and ready for taping.


The OP stated that at least 2 walls have this backing. If that is the case, there is a good probability that all the walls are like this. How far should the OP go?

siffleur


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## Domo (Nov 9, 2018)

siffleur said:


> The OP stated that at least 2 walls have this backing. If that is the case, there is a good probability that all the walls are like this. How far should the OP go?
> 
> siffleur


Well, the walls are deteriorating, right? - so he could patch and live with cracks forever and patch forever.

If it's just two walls he's talking about (maybe) eight sheets of wallboard if they're 16 X 16 rooms. (and you can get 12' wallboard for fewer seams)

Or, do the job completely, one room at a time. It's up to OP to find the starting and stopping point. I tend to think he'll learn a lot about his house and upkeep PLUS he'll earn a lot of bragging points for when it's done and he has "the party."

If it's one wall or the entire house, he'd be half way through the project by the time everyone is through discussing the issue for him on this forum.

Benefits; he can inspect, insulate, puff boric acid to kill bugs, install hidden multimedia cabling, add outlets, install windows, change doorways very easily when all you have is studs.

Yes, I've pulled lath and plaster off the entire inside of a house a few times.. Glad I wore a mask and googles, had a couple of friends and could afford beer (I'm actually a scotch drinker - but the work was thirsty). Hot, nasty, dusty, heavy and very rewarding when you take an old house and make it ALL yours on the inside.

I'm 68 and the last room I gutted down to the masonry outer walls and studs on the interior walls was for my kitchen remodel in July 2017. I was too cheap to hire anyone :vs_laugh: so my DW and I did it all and loved it.


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## KingJames603 (Aug 18, 2016)

Thank you ClarenceBauer on the clarification on the type of wall I have. The second photo shows more of the lath under the wall it had barnboard I removed, which I hired a guy to put 1/4 inch drywall over the lath durabond and all-purpose mud. I think siffleur is right about most of the walls, since most of the walls are in good shape I dont have to gut the walls just repair them. The first photo I found that I needed to make a bigger section which I'll make a 7" x 16" section of 3/8" sheetrock to install in the broken section, durabond, ezsand and top coat with all-purpose mud. Originally I had the idea of cutting two small holes in the lath to screw 1" x 2" furring strips with a shim attached behind the lath and plasterboard for a small patch with 3/8" sheetrock or glue or durabond the back of the drywall to the lath.


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## ClarenceBauer (Mar 4, 2005)

With the type of plaster system you have installed in the residence you can repair all the areas using a perlite plaster to fill the holes as long as the Rock lath backer is in place if missing use most any type drywall board installed as backing. After the repairs are made use a good Veneer plaster to finish the repaired area. You could also use a Venetian Plaster. If you want or need to refinish the complete wall area you can use a product like Master of Plaster & refinish the complete wall surface which would eliminate any sign of repairs.
If a veneer plaster is used there is no sanding required no dust & you can finish in less time.
Using a good veneer plaster if there are cracks at this time they can be covered & not reappear at a later date if you follow the correct procedure as instructed by the veneer manufacture.
Some other Veneer Plaster products:
American Clay
Variance Plaster
TexSton Plaster
Marble Crete also has a veneer plaster.

The best & most user friendly is Master of Plaster.


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## coupe (Nov 25, 2011)

KingJames603 said:


> I have to make a drywall patch which the surface feels loose. When I opened a hole with the loose surface I noticed a backer board that I cant put a 1x2 furring strip behind due to that backerboard. I would have to make a patch about 3" x 8" between the studs. The wall and the backerboard is 1/2" depth. The first picture shows the hole in the wall and the second picture shows another wall in my house that has a view of what the backerboard panels look like. How would I fix this, with a 3/8 drywall patch adhered to the back with joint compound or glue, open a hole in the backerboard to screw in the furring strips, or some other method?


I'm certainly no expert on plaster walls.But, the first icture looks to me like wood lathing? But no gaps between to keylock the plaster. I think I'd go with the old fashion California patch on that hole.

If you have a piece of 3/8" drywall? I'd square that hole to the size needed3"x8" or whatever cut your 3/8" frywall to a 6"x10" piece, turn it over and mark out your 3"x8" score it with your drywall knife, tear the back aper off, then scrape the gypsum off as smooth as you can leaving only the front white paper, you want all the gypsum off any little pieces will make your spackle knife carry those little bumps throuout your finishing tools I'd drill a few 1/2" or 3/4" holes in the wood, mix a batch of 20 minute quick set to a consistency where it holds together well but doesn't run out. I'd slap some of the quick set onto the wood lath with force to drive it through the drilled holes, while its setting sread a layer of ready mix joint compound on the back of the 3/8 drywall and set it in the opening with a larger piece I'd push it in and brace the larger piece against it making it even with the rest of the wall. The next morning, pull the paper back of your patch piece and coat it with joint comound, use a 6" spackle knife to smooth it out all the way around, let that dry good. Then two coats of joint compound over that, the first with a 12" trowel, the second with a 16" trowel. Holding the trowels at a slight angle at which ever side you start and slowly raise the trowel to it's edge as you come to the end. I'd even use a spray bottle to moisten the wood lath to start having no completely dry surfaces anywhere throughout the processes, the water is what binds everything together as one piece. Then use a good sponge to smooth it up and get the edges down, not too wet! the water will cause the paper to roll up. When it's all dry simply paint and you're done

good luck and god bless

Larry/coupe


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## ClarenceBauer (Mar 4, 2005)

There is no wood lath in the wall system in the photo's what you see is the Gypsum lath board joint.


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## coupe (Nov 25, 2011)

ClarenceBauer said:


> There is no wood lath in the wall system in the photo's what you see is the Gypsum lath board joint.


No arguement here 
ClarenceBauer.I simply offered the simplest fix with the least demo and rebuild to geet his wall fixed

Larry/coupe


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