I recently demolished an unsafe staircase from the first to second floor in my old (circa 1850) farmhouse. I was able to save a lot of the old plaster over lath but there are sections that need to be redone. All of the areas to be patched still have the old lath as a base so what should I use to feather the exposed lath to the existing plaster? I’d say I need to fill no more than 1/4 inch to get me level withthe old surface.
Thanks all…
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Replies
espo... if you take the lath sections you have exposed off and replace it with "rock lath ( 3/8" thick ) or drywall or blueboard.. you can patch in
if the surface is curved.. you can use metal lath... and a base coat, scratch coat & finish cot..
or you can use metal lath , or rock lath and build up with Durabond.. then finish with joint compound
if you use the rock lath ( 3/8 ) you'll need a two coat... either plaster or Durabond.. then a finish coat
if you are going to patch with gypsum.. you have to get your thickness slightly less that the adjacent finish and skim-coat your gypsum to match the old plaster
in short.... you can do it any way you want.. as long as you have a plan
Mike, Up early too I see... I'm thinking that 3/8" rock will stand proud of the existing finished surface. Do you think durabond trowled over the existing lath and feathered to the old plaster will do it?...Thanks for the advice...
Mike,
I re-read your original post and I think I get it. I should probably just remove the old lath then apply the rock, then level with durabond & joint compound. Thanks again.
exactly.... lath & plaster usually adds up to about 3/4" in thickness3/8 for the lath ..... & 3/8 for the 3-coat plasterMike Smith Rhode Island : Design / Build / Repair / Restore
If you are just talking patches, secure existing lath and coat with structolte, two coats, and you can finish with topping or all purpose, if you are uncomfortable working with plaster. Use a bonding agent with the structolite, available where structolite is sold.
Ruff, If I could jump in w/ a related question: just finished a seismic retrofit in a finished basement. The walls are plastered with a sandy (yet smooth) finish over wood lathe. now we've got plywood sheathing on 40 percent of the walls, and it comes < 3/16" within (below) flush to the plaster wherever they meet. Ideally, I could skim the plywood just enough to cover it's texture, with an extremely low profile lathe material -if needed. I'm worried though that such a thin coat over plywood may be doomed to cracking, especially if I'm coming from a deep fill (the gap between materials) and going so thin. How can I bridge the two surfaces? what kind of reinforcement and patching pruduct would suit this situation? thanks
I would guess the existing plaster is a brown coat that was finished smooth.
I guessing two options.
1. use a bonding agent over the plaster, after knocking loose material off and lath over the plywood and float the whole thing even with plaster or better yet that D-mix that is getting so much print on the forum (do a search)
2. Just rock over it all and finish. Furring the 3/16th if you want.Just use long screws over the plaster.
Option two is the way I'd go.
I've done quite a bit of it here in my 1680 house.
For me, first coating the lath with "structolite" worked best...then plaster mixed with a hint of either milk or vinegar which gives you more working time.
Be wall....I mean well
a...
The secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
Hmmmm. Strutolite. Don't know if I've seen it in the big box stores in Rochester...Do you think somehting like Durabond 90 would serve the same purpose Andy?Dave
Go to a drywall supply house, Sructolite is a gypsum-perilite mix and there or other brands also, I believe.
It comes in a 50 lb. bag and is cheap. Home depot don't have it.
Call around. Durabond will do it, but it is not really the right material.
that's what I was gonna say ...
patch the plaster with .... uh ... plaster?
Jeff Buck Construction
Artistry in Carpentry
Pgh, PA
yeh, patch plaster w/plaster but on the lathe...structolite has worked best for me then the plaster mixed with a hint of milk or vinegar and then the water.The HD by me has it and there are several drywall places by me that has it as well.
Its cheap too
Be well Free
a...The secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
I honor the place in you where the entire universe resides,
I honor the place in you of love, of light, of truth, of peace.
I honor the place within you where if you are in that place in you
and I am in that place in me, there is only one of us.
As the other poster said "For me, first coating the lath with "structolite" worked best"
I have had good luck with this stuff as well, the HD where I live does/or did sell it and I can't remember why or when I bought such a huge bag but it has come in handy more then once. I covered it with durabond and used tape on the edges where the old met new, maybe over kill but it has stood up very well. just slather it on and there you go. I still have a stash in the basement. I say go for that, I will again. It mixes nice and is pretty easy to use.
I run into this in older houses pretty frequently. Typically, I'll cut pieces of 1/4" thick drywall to fill-in the larger areas and screw that to the wood lath. Then, I'll fill voids with a coat of durabond, followed by subsequent layers of easy sand or ready-mixed joint compound to feather into adjacent areas. If a small area, or if 1/4" drywall is too thick, sometimes I'll cut a piece of metal lath and staple that to the wood lath with my 1/4" crown stapler and then use durabond. I would not recommend removing the wood lath.
Good luck!
"Preach the Gospel at all times; if necessary, use words." - St. Francis of Assisi
I agree w/ steve-o. Keep the lath, some of that old framing needs it for structural support. I've had good success with thin sheetrock, tape it in, needs fewer coats, faster dry time.
Thanks guy, I got my workin papers...Dave
When you tape, do you use paper or fiberglass? I've always used fiberglass to mate old-with-new materials so that I don't have to worry about any bubbles under the paper, but was wondering what others do?
So for someone who is plaster-challenged, would the distillation of advice be:1. structolite
2. durabond
3. skim coat (mebbe D-mix?)
I think I do like fiberglass better with plaster. Also does anyone use "Fix-all" in powder form, or is it the same as the other products being mentioned here.