# Wood Lath



## jefsboys (Jul 12, 2010)

Hello,

Writing from St. Louis, MO area. I recently purchased a wonderful house built in 1904, 2 1/2 stories with full basement. Just turned the the second story light circuit on the other day after replacing the knob and tube throughout the house.... wow.... that was a job.
Now I am looking forward to some crack repair in the wood lath plaster covered walls. I have a couple of walls/ceiling completely removed and will be re-doing them 3-coat plaster. I took some bad advice at first and removed those walls... hind sight coupled with much reading and research says I should have/could have fixed the walls and ceilings I removed. At any rate... here I am now and I am beginning to repair the plaster cracks and holes and put up a few new walls and ceilings.

I guess my first question would be.....
I am beginning with crack repair after removol of loose plaster, vacuuming out and slightly under cutting the cracks. 
Most of my reading has led me to purchase durabond, which I got in the 90 minute set time. I have a bonding agent I will be applying as well.
Are there any issues with adding some sand to the durabond to try and match the old texture?
I am trying these first cracks where they won't be very visible.

Thanks in advance for your time,

Jeffrey


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## jules4 (Jul 7, 2010)

You can add clean sharp/masonry sand to Durabond. 

Also, you don't need any bonding agent - just make sure the old lath and plaster are damp (not dripping!) when you place the fresh Durabond/plaster so that they don't suck the water out of it. However, when doing a whole wall it's easier to just paint the laths in bonding agent than to keep spraying them - but don't bother getting some fancy plaster specific agent, generic masonry/concrete bonding agent is fine - the keys are what hold the plaster on, it doesn't need any special plaster "glue".

I've actually been doing some 3 coat plaster walls at my parent's 200+ year-old cottage and I don't envy you doing full ceilings. I managed to avoid having any full ceiling tear outs - in places where the ceiling was sagging due to broken keys I put in a bunch of plaster washers and, tightening each washer only a little at a time, gradually cinched the ceiling back into place (didn't even crack it). 

I don't know if you've decided on what you're using for the plaster yet, but if you don't have your heart set on doing traditional lime, I recommend a 2:1 mix of Structolite and Diamond Veneer Plaster for the scratch coat, a 1:1 mix for the brown, and a 1:3 mix for the top coat. And round the corners off your trowels with a slight upward bevel so you don't gouge the plaster when smoothing - makes a big difference.

I applaud you for going with good old-fashioned "wet wall" - much nicer than that modern dry stuff (plus, there's no sanding ). 

Julia

P.S. I hope you're re-nailing the old laths with galvanized nails before plastering them.


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## jefsboys (Jul 12, 2010)

Thanks for your reply and the info.
I did sort through in my mind and realized I didn't need to use the bonding agent for applying the durabond. 
I will renail the lath strips, clean the old keys out and be putting metal lath over top, at least on the ceilings, but am also thinking about doing metal lath over the wood on the walls as well. I already got the masonry/concrete bonding agent.

As far as what plaster I am going to use....
I have some structolite base I am going to be using on some larger hole repairs with Kal Kote finish.
For the complete walls and ceilings I actually talked with a rep from USG and they confirmed my research on the products to use. I think I will be ordering some Structo Base and Red Top Finishing plaster. The thing with the Structo Base is that I will have to add the sand aggregate, which will be ok.

I am working on getting one of the bathrooms completed so we can move in; no fully working bathroom yet. I had a family member put porcelain tiles on the floor and lower part of the wall, the wall had tiles on it when we moved in. The part where the tiles transition to the wall is pretty ugly in spots(please see attached pic). Can you give some advice on how to approach that please? The simpler the better. I simply want to have painted wall from where the wall tile stops all the way to the ceiling.

I have attached another pic...
The paint in the bathroom was very cracked, looked like an eggshell. We have been scraping off the cracked paint and now the underlying finish plaster doesn't look so well. It is certainly good enough to put a primer and paint but I was thinking maybe even another finish coat on that might be needed. Will you please look at the attached and let me know what your thoughts on that is?

I will probably have a ton more questions. 


Thanks,

Jeff


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## jules4 (Jul 7, 2010)

That's the nice thing about the structolite-diamond mix, no need to add aggregate to any of the layers (other than the perlite that's already in the structolite). 

If you want simple, fix the major hole(s) in the bathroom wall and then just paper over the plaster with "paintable wall paper/covering" (it's heavier then normal wall paper - more like fabric). Nothing could be easier and it will give you a nice surface. I plan to do this in a stairway that never had a top coat put on (they left it at the brown coat and then just papered over it).

An alternative to paper is to remove the top coat from the old plaster (it usually separates pretty easily with a metal putty knife) and put a new top coat on. (Even if you paper for now, you could always go back and do this later.)

Cheers,
Julia


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## restored (11 mo ago)

I have typed in various questions asking the same thing and in thread/forum and every other one, getting one straight answer doesn't happen. Simple question. Doing plaster repair, if I knew I would receive 10 different answers of which 7 aren't even related to the one simple question being asked, I would have just removed every bit of old plaster and hung new blue board. Don't ask the question if one can skim coat regular drywall with plaster. Every answer will vary and stay related to the basic question. So here goes. due to a lack of products available and a supply chain issue, thank you joe B, Will Durabond 90 or 45 bond to the old wood lath???? Yes the wood has been sealed with plaster bonding agent. I'm Not asking how to apply durabond panels. In fact, doing only remodeling since 1980, I have never even heard or seen durabond panels. THe questions I have asked hasn't HAS NOT mentioned panels. The answers have included batter the back of the panel with a durabon and stick to the wood lath. I'm lost with this answer and can only imagine what the average homeowner who hasn't taped tens of thousands of drywall sheets must think, as they attempt to figure out how to repair their old plaster. Don't even mention filling the voids with drywall. 3/4" may be the average finished plaster thickness, but I have seen it vary from less than 1/8" coat of plaster to 3/4" thick coat of plaster. So common sense tell you, removing a area of that section, and properly preparing the butting areas so the plaster is sound, applying a bonding agent over the wood lath, with the keyway spacing exposed, WILL DURABOND BOD TO THE WOOD LATH?? I ordered a USC base coat coat plaster, from the local lumber yard, requesting structolite, and received one bag of diamond and one bag of Imperial basecoat veneer plaster. Directions not to exceed 3/16" thick. People have asked questions, can I remove the old plaster and patch will 3/8" drywall, and the pros have answered the 3/8" isn't thick enough to support a patch. Well if the area is large enough and it butts any trim at all, baseboard, door or window trim, then the finished wall exceeds the the outside surface of the trim. Very specific questions with very unrelate answers accounting for the various variables that can exist while doing wall repairs. In my case I'm doing a stairway, over half the walls are in very good condition. The parts that couldn't be repaired with plaster washers, adhesives injected behind the old plaster, leaves 3 alternatives. First total removal of all plaster. In 95% of this situation the laths remain and only 3/8 or 1/4" drywall would work to maintain the small reveal on all the finish work. Requiring flat taping these areas to avoid cracking. Most often trying to add a 1/4" molding to the existing trim would exceed the outer wall surface. #2 removing all the plaster and all the laths, adding blocking where necessary to support new drywall, blueboard, etc. All still needing to be installed as perfect as possible as it will butt all trim. Okay all the trim can be removed, causing issues with doors which relying on the casings to help support the jambs which becomes extremely costly and not consistent with economics. So I ask again, will durabond 90 or 45 the bag we all cash and carry from the big box store, BOND TO THE LATH? We can all walk into one of those stores and walk out with a veneer plaster. Of which goes on over a base coat coat plaster. You won't walk out with a basecoat plaster in NH at any of these stores. You can order online and in my case was told it would arrive in 2 weeks. That was 3 1/2 weeks ago. So I will ask again, will durabond bond to wood lath? I'm not asking if I should remove sections of plaster and replace with appropriate thickness drywall . Why? Because I have already done that. It's the outside corners, its the 10 SF in the middle of the wall that has damaged 1/8 to 3/16" missing plaster that needs to be base coated and then finished coated. Please stick to answering the a direct question with a direct answer. I'm still waiting to hear back from USG, and the general consensus is there are a few real plaster products that will bond and use those. Not a basecoat veneer or a durabond. The you tube videos are full of using these in very clear cut situations that don't apply to most questions asked. Type in the same question I asked and you will be brought to a answer from one forum contributor,you can repair a chimney that has missing plaster with durabond then finish coat with regular drywall compound. Not a stick of wood on the chimney. My follow up question would be, if the bond is adequate, and now I have a patch that is durabond which butts the old plaster is a fibermesh tape used with plaster be the go to tape to avoid cracking in the future and best bond those two areas together. Be prepared, there are a half dozen different tape products that can be used. An 3 dozen different opinions. Each job varies both in size and issues. Cost always plays the biggest part, then time, and the finished product. So will durabond bond to wood lath, these sections are clean , sealed, average about 10" wide up to 5 ft. long. Where the laths have been removed, and the stud spacing is 16" OC, for my project I am using a 1/2 drywall or blue board and skim coating a plaster veneer over, after taping the seams. So my question about bonding to wood doesn't apply, but the answers, apply to off the charts do and don'ts. I wish I would have just removed it all and hung new blue board. In my case, it's my own time, as it is with most DIYers. Supplying them with direct answers to basic questions, should be the objective of all who take part in these forums. Bonding to wood, it the question, not a block chimney. If the home owner ask if 3/8" drywall will work, answer the question based on knowledge. If it is being backed by lath that is sound yes 3/8" drywall will work. It will allow you to skim coat 1 a strong 1/8" veneer plaster of which is hard as a rock. You will need to be aware of the thickness as you butt the existing trim. Flat tape these areas with a stick on fibermesh tape. This will eliminate using a compound embedding the paper tape into it, and squeezing out the excess. Keep in mind it will take 2 more coats of compound to properly cover the tape. If using a durabond in this situation it tends to be thicker, sets fast and difficult to sand. Using plaster with a setting retarder, and wetting the area while you work it like frosting a cake will be stronger, and with experience little or no sanding. You can lightly coat with joint compound to smooth out and left with minimum sanding . So will durabond bond to wood lath. Will it help on smaller areas only and if I add wood glue to the mixture for help in bonding. Applying all these products takes experience. I have found the easier method of skim coating and plaster wall in reasonable condition is to use regular joint compound. Tape even small holes with the tape of your choice. feathering out the entire area to attain a flat surface, is where experience plays a huge part. The choice of the knifes or trowels also are important. plasters trowels are flat. Drywall trowels have a slight curve. The reason for this lies with a piece of drywall itself. The edges of drywall, length wise is indented, a smaller thickness to allow for tape and mud. The seam to receive a liberal coat of compound or durabond, (harder to work with) then a paper tape with the center crease in the tape pointing out towards you. Remove the excess mud with a 6" drywall knife, so it is smooth. Remove any left over ridges beyond the seam. The second coat use a 10 or 12" drywall trowel. This will have a small outward bow like a bow and arrow. This allows for the mud to fill the concave section of the drywall to fill and be feathered in the process. After drying, a day in normal circumstances, repeat this process using a 14 or 16" drywall trowel also has the bow in the trowel. If compound ridges remain on the outer area of the trowel remove with your 6" knive. If you wish to skim coat the drywall with a veneer plaster for a harder more durable surface, I tape and apply the second coat only. At this point you will basically have a flat surface to be working with and the plaster skim coat can them be a consistent 1/8" , depending on your job specific issues. Little to no sanding is required with plastering. To achieve this takes practice and experience. The plaster with bond eo the drywall compound, just set faster because the compound will suck the moisture from plaster at a quicker rate. The ends of Drywall, what we call butt joints are done the same but do not have the concave indent that the flat sections length wise have. This may take an extra coat on either side of the seam with the longer trowel to feather out further. Eliminate butt joints where you can. install the drywall so the butts land over a door or window, preferably in the middle so the compound build up doesn't affect the trim to be applied. As much. Every job in doing repairs and rehabs are different. age of house will determine many factors. Research your products beforehand. Do your best to eliminate having to do it all over again. Sorry for the long 2 cents. Not sure if one can reach out wo those who post, if so and have questions, if I can answer I would be happy to.


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## SW Dweller (Jan 6, 2021)

Full basement. Settling starts at the bottom. Before playing plasterer, better check for support in the basement. No sense doing a good job to have it crack again.

FYI houses settle they all do. Mine is slab on grade made in 1988 and I have ceiling issues.


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