"Traditional" plaster?

[duburban]

Anyone still know how to hydrate and mix lime plaster?

I have plenty of experience w/ lime based venetian plaster but never done a from scratch. I'd like to retrace some of the historical mixes (minus the horse hair) and do a cement modified lime plaster with marble agg or super fine sand, maybe with a bonding gyp board base.

Ideas? Plaster geeks?

 

[c_dwyer]

No solution, but another question on plaster. We're planning to gut a section of a very old house that has an interior of lath and plaster. Was asbestos or any other nasties ever used? I'm thinking the era was the 1930's or 40's, but not later.

 

[peter halle]

Anyone still know how to hydrate and mix lime plaster?

I have plenty of experience w/ lime based venetian plaster but never done a from scratch. I'd like to retrace some of the historical mixes (minus the horse hair) and do a cement modified lime plaster with marble agg or super fine sand, maybe with a bonding gyp board base.

Ideas? Plaster geeks?

Perhaps [member=550]Tinker[/member] can help.

Peter

 

[peter halle]

No solution, but another question on plaster. We're planning to gut a section of a very old house that has an interior of lath and plaster. Was asbestos or any other nasties ever used? I'm thinking the era was the 1930's or 40's, but not later.

You should get it tested just to be safe.

Peter

 

[Goz]

Not sure how much experience you have with plaster, so this might be more background information than you need.

National Park Service - Technical Preservation Brief 21 - Preserving and Restoring Flat Plaster.  General information on plaster, restoration techniques, etc.https://www.nps.gov/tps/how-to-preserve/briefs/21-flat-plaster.htm

General Service Administration - Lathing and Plastering Walls and Ceilings.  Recommended ratios for brown coat, scratch coat, etc.  Detailed descriptions of recommended surface preparation and application procedures.https://www.gsa.gov/real-estate/his...resources/technical-documents?Form_Load=88538

General Service Administration - Selected Reading on Lath and Plaster.  List of additional resources.https://www.gsa.gov/real-estate/his...resources/technical-documents?Form_Load=88491

Hope these help!

 

[duburban]

Not sure how much experience you have with plaster, so this might be more background information than you need.

National Park Service - Technical Preservation Brief 21 - Preserving and Restoring Flat Plaster.  General information on plaster, restoration techniques, etc.https://www.nps.gov/tps/how-to-preserve/briefs/21-flat-plaster.htm

General Service Administration - Lathing and Plastering Walls and Ceilings.  Recommended ratios for brown coat, scratch coat, etc.  Detailed descriptions of recommended surface preparation and application procedures.
https://www.gsa.gov/real-estate/his...resources/technical-documents?Form_Load=88538

General Service Administration - Selected Reading on Lath and Plaster.  List of additional resources.https://www.gsa.gov/real-estate/his...resources/technical-documents?Form_Load=88491

Hope these help!

These are great, thanks.

I'm curious about getting a little whacky with it and land somewhere between traditional and ardex so that I can use it as a surface backsplash in a kitchen. I'll start with learning how to make putty though

 

[Tinker]

Anyone still know how to hydrate and mix lime plaster?

I have plenty of experience w/ lime based venetian plaster but never done a from scratch. I'd like to retrace some of the historical mixes (minus the horse hair) and do a cement modified lime plaster with marble agg or super fine sand, maybe with a bonding gyp board base.

Ideas? Plaster geeks?

Perhaps [member=550]Tinker[/member] can help.

Peter

Way back when I was just out of high school,  I got a job as an apprentice (translation: gofer) mason. The main part of my boss's trade was stone work. At some point along the way, we got involved with plastering.  "Brown coat" base was, except for the material used, just like stucco that we did over foundation, mostly over blockwork. the brown coat had to be mixed perfectly every time. That was usually my job. 

Eventually, we got into "White coat" that was even more fussy. The boss always mixed that material. For Brown coat, we (I) used a big "mortar tub" was dumped one or two bags of plaster into which water was added as plaster and water was mixed with a very large hoe. that hoe was at least four or five times larger than your every day Home Depot garden hoe that most are familiar with today. The water had to be added at the very start in just the right amount and mixed very quickly. to just the right consistency and with no lumps. That was an easy job compared to mixing of white coat.

For white coat, we used "Unslaked" white lime. That had to be handled with care. Water was poured into the same sized mixing tub as the brown coat had been mixed in, but never the same tub.  Then the lime was added very carefully. Never put the lime into the box first and the add the water. I you add the water to the lime, there could be an explosion and any bystander could be badly burned. Whenever using unslaked lime, we always had a bottle of caster oil in our pocket.  A burn from a caustic source can be as dangerous as burn from an acid source. The castor oil was to immediately flush out an eye if the lime had splashed onto a face.  You did not wait for a doc or want to be spending precious seconds searching for a first aid box, you just reached into your pocket and poured castor oil into your eyes. Fortunately, nobody in our crew ever had to do that. BUT, we were always prepared.

I usually did the mixing of the hot lime.  I would mix up enough at the end of the day for tomorrow's project and it would be left in the tub overnite. We had a big sheet of plywood that we did the final mixing of the white coat on. i never did that part, my arms had been cut off at child birth, or my grandparents had been small, or some sort of excuse, I could not reach across that board to do the mixing. The slaked lime was placed on the mixing board. A container of "plaster paris" (you can get hat stuff in hobby shops. It is not dangerous to use.) At this point, I did not get involved.  The boss always handled the final mixing.  Slaked lime was placed into a big donut into which he plaster paris and water ws dumped. Then the batch was mixed  by hand much as my wife later in my days would mix ingredients into a bread dough when needing the dough to make bread. By hat time (back to the mixing of white coat plaster) the lime was supposedly not any more dangerous. We still carried our bottles of castor oil (at least I did) just in case. once the final mixing had been completed, the batch was fed to the plastering crew. and applied in very thin coat to go over the brown coat.

By the time I had advanced to the point I could apply white coat to finish the job, a new invention came along that made all this typing to have no more meaning than if I were typing a story about dinosaurs. I suppose somewhere in this world, somebody is still working with brown coat, hot lime and white plaster. The last time i did a repair to white plaster, i cut into the plaster and wood lathe, replaced with a piece of sheet rock and troweled on joint cement. Three coats of joint cement and one was left with no clue that a repair had ever been made. I much prefer that method to the ancient methods I grew into the trade with.

Oh, BTW, all that was when I was only ...... I can't remember how long ago. Must have been when I was 38.

Tinker

A little side note: yesterday, I got stuck with my snow plow and had to get dragged out. While being dragged out, three of us were working together. I was operating the shovel with the hickory boom, my grandson was driving my truck and my son was driving the truck that was dragging my truck out.  Three generations of snow plow guys working together in a snow storm. You don't see that sort of foolishness very often.  And, the old f--- was the only one who knows how to use a shovel. The younger generation is definitely smarter.

 

[Knight Woodworks]

No solution, but another question on plaster. We're planning to gut a section of a very old house that has an interior of lath and plaster. Was asbestos or any other nasties ever used? I'm thinking the era was the 1930's or 40's, but not later.

According to my late father, a plasterer, yes asbestos was sometimes used. Definitely test it.

John

 

[Tinker]

It seems that I remember mntion of asbestos having been used in plaster. I do remember that horse hair was used back  wood lace was used behind the he gown coat plaster (hers called bon coach "scratch coat" as mentioned above in one post.

One job i did when first stringy own biz, I had to make a smll repair to a kitchen ceiling. he white coat was peeling from a "bubble" in the center of the bown coat ceiling.  I had checked in the attic and discovered the entire ceiling had been plastered over wood lathes.  I gave a price forreplcng the entire ceiling to which the customer rejected. "It is only a little patch" they said.  I would not take the job if they expected any less.  I explained that as son as i tied to cut out for the little patch that the entire ceiling might come down.

Long story short, as soon as I started cutting away around the edge of the  patch,i had he entire ceiling, lathe and plaster down on the floor. That was the first job I ever did wearing a hard hat.  that was in the days when hard hats hat the big wide brim. The only damage to me was as the plaster and some of the lathe came down, that big tipped forward and bent my glasses frames and bruised and cut my nose. The reason the entire ceiling comedown other than that the plaster was probably 75 or 80 years old, it was mixed with long strands of horse hair. It was like a net holding the plaster together.  Some of the strands were over two feet, or maybe three feet in length. Altho the strands were randomly arranged, hey were almost in a weave. Some pieces of plaster came down in three foot sections while other pieces were only two or three inches in cross section. Itall depended on the lengths of hair and the texture. If the entire house was plastered using horse hair, there had to have been a lot of horses used.

That was actually the first job I had ever used sheet rock and the joint cement used was dry mixed and came in bags. A bag of joint cement was poured into a small mixing tub and mixd with a hoe the same way I would mix a batch of plaster. Only in much smaller batches. Once I learned how to use sheet rock and joint cement, I never went back to using plaster again. Even if possible to patch a small hole in a wall or ceiling, I ould cut a "key" of sheet rock and, if necessary, double or triple the key and patch in with joint cement. Sometimes, we used joint cement in between layers of sheet rock in the patch like we use lue to do laminations in woodwork. There was a lot of learning in going from wood lathe to rock lathe andoing from plaster to sheet rock and joint cement. The tools even changed.  I had learned to stucco using a "hawk" which was about 12" square piece of stiff alluminum with a round handle in he center underneath and a plaster trowel. I never got away from using the hawk. Also,i never got to where I would use anything other than various sized "putty knifes" up to sometimes as mid as ten inches. I used a 4" putty knife to do corners and flat tape applications.  Wider knifes with each layer of the joint built up. I never got the hang of using other specialized tools than what I describe here. I only did taping in winters to fill in the slack time when too cold toward outside.

I have watched other tapers who could do an entire house in the same time I could do a room or two. They now use excelerator in the mix so a room can be done in three layers or more in one day. I tried using an excelerator one time and got into all sorts of trouble.  Never tried again. I guess now one can get quick setting joint cement that does not need any excelerator.  I have not done any sheet rock work in about twenty years. that was either in my own house, or my daughter's and son's houses.  Probably haven't done any paying jobs of sheetrock for nearly 35 years.  A lot has changed. I go back even further to the using of brown coat plaster and white coat.  I had just learned how to do white coat when sheet rock came along and that was the biggest change in my experience.
Tinker

 

[mrFinpgh]

Yes.  It was used as a binder in the brown coats.  Usually not a very large amount but enough to be considered asbestos containing materials.  It's worth getting tested.  My 1930s row house has 2% white asbestos in the brown coat.

As a rule, it's a good idea to protect yourself when demoing plaster.  Tinker mentions the more immediate danger - if the plaster is in bad shape, it can come down in bigger batches than you might expect.  When I redid my bathroom, I took the casing off the window and half a wall fell off.  Fortunately, I was in rrp mode and the place was sealed up well anyways because of some lead paint stuff, but the heavy plaster falling around me was not a good time.  Non asbestos containing dust is also very irritating and not a good idea to breath.

What I learned from the asbestos contractor I spoke with was that the key is keep things wet and use a surfactant (like dish soap).  Keeping the air moist helps to also prevent a lot of dust.  This is as simple as misting the space with a chapin sprayer occasionally.  None of this substitutes for good sealing and PPE, but it does help to reduce total exposure risk.  It also makes it a bit easier to clean up (although the plastic floor can get slippery).

 

[Tinker]

When I started my apprenticeship in mason trades, there was no such worries about asbestos. It was 1949 and housing trades had suffered thru the war years and just getting warmed up when Korea started getting more than warm.  There were new houses going up, but most of the constuction was remodeling.  A lot of tearing out to extend a room, or even whole new add-on structures. No body worried about damage ing lungs, especially lungs of the gofers. It was fifteen or twenty years along the road before the dangers of asbestos were known, or admitted to. I am lucky. I was willing to do the dirty work of tearing out, after the tearing out, I was the one in the crew who did the shovel and pick work of digging a trench for footings, and then I was the one who mixed the mud. Before  it became mud, it was always a dusty project. I am lucky i never discovered what all the noise about asbestos is all about. I don't plan to find out.  I was involved with probably plaster dust with asbestos, pipe insulation mostly asbestos where I worked with plumbers, and doing siding jobs where I had to rip off asbestos shingles.  By the time I got to ripping off asbestos shingles, I was smart enough to keep the shingles wet.  not because I was knowledgeable about the hazards of asbestos, but because i just did not like the dust from breaking those shingles. I guess my aunt had it right when she used to tell me "Ignorance is Bliss."
Tinker

 

[duburban]

To give more detail about why I am interested in using a custom mix:

1. backsplash. have more water resistance, hard like cement, not gypsum
2. appearance. being able to see aggregate or burnish down into a polish
3. to approach the look and feel of "traditional" visually evident hand applied finishes.

I have used "imperial" and "diamond" type plasters but they would not be my first choice behind a stove or sink.

This is why I'm saying somewhere in the spectrum between traditional and ardex.

 

[Tinker]

I have done cement plaster over rock lathe as well as over wire lathe. One job was cement stucco over wire lathe with a "spatter-dash" finish of pea gravel on an outside wall. That type of finish can be smoothed out or left very rough with the stones showing and looking like they are just thrown at the wall.  Basically, that is what was done.The cement stucco can be inside or outside, either/or. It is very durable and impervious to water. I have used it on outside beds and inside walls of our own bathroom. It is not a mix you can use over rock lathe without starting with plaster and some times some wire reinforcement that it can cling to. You do have to start with at least one coat of brown coat plaster and scratch it if overrock lathe. You can trowel the top coat very smooth, or you can use only a wood float finish that will look sandy. I never tried pollishing that mix, but I am sure it can be done. If you want to know how I mixed and applied, let me know and I will PM to you.  I have to go out and shovel snow before the boss gets back. She is bringing FOOD AND WINE. Let's not aggravate.
Tinker

 

[BarneyD]

I come from a long line of plasterers - 3 generations for sure, probably 4. But sadly I inherited none of those genes. So apologies to the OP for lack of knowledgeable content. Somewhere though I have a book written by my grandfather called "Practical Plastering". I may have given it to my son. I just checked on Amazon and it's apparently out of print. But maybe there might be something useful in there if you can find an old copy. The author was Byron Dalton. Published I think in 1937.

Barney

 

[Tinker]

I come from a long line of plasterers - 3 generations for sure, probably 4. But sadly I inherited none of those genes. So apologies to the OP for lack of knowledgeable content. Somewhere though I have a book written by my grandfather called "Practical Plastering". I may have given it to my son. I just checked on Amazon and it's apparently out of print. But maybe there might be something useful in there if you can find an old copy. The author was Byron Dalton. Published I think in 1937.

Barney

[member=61023]BarneyD[/member] , I'm the only one in my family that had anything to do with masonry.  I do have a funny story about when I was learning the trade.  My boss had done a few small plaster jobs and I had done alright with stucco on outside walls. I was beginning to pick up plastering skills and had done a couple of closets while the boss was doing the rooms.  When it came to plastering his own house, he figured it was too big a job to tackle alone, so he hired another contractor.  I stopped by one afternoon to see how the job was going.  It was always my job to set up staging and I was interested to catch a few pointers in that part of the project as well as to observe how "real" plasters did their job. I was met at the door by my boss who led me upstairs to the room the crew was working in.

I was surprised to see no sign of any staging.The three man crew were brothers, all about the  same height, which for  plastering ceilings was a desirable situation. It also helped that each of the brothers were about 6'6" tall and did not need any scaffolding to reach the ceiling.  I indicated to my boss my surprise to which he suggested I go around the corner and check in the closet.  There, working from a couple of ladders so he could reach the ceiling was a midget who was barely 4'6", give or take.

Years later, I was working on a job and during BS session, I was telling this story to the two carpenters. One, I had known for many years.  The other, as I went on with my story exclaimed, "Those were my uncles. The midget was a cousin and he always did the closets on the jobs."
Tinker

 

[BarneyD]

[member=550]Tinker[/member] I know it's been suggested before, but I do hope you'll write a book some day. I love your reminiscing. You bring back a lot of fond memories.

My mom and dad bought their first home in I think 1951. It was just a "shell" - exterior finished, interior not. After several months my dad had enough of the interior plastered that we could move in. I remember as a long lad watching him do all the plastering. I was too young to be of any help but I'm sure I was quite a nuisance with all the "why?" questions. Anyway, when I entered first grade my dad announced that he was going to finish off part of the basement into a family room. He finished it the year I graduated from college. My folks invited some friends and neighbors over for a christening party. Somebody said the new family room looked real nice. And my mother said " Yeah, and it only took him 15 years." And which point my dad proclaimed "Yep, finished early, and under budget, too!"

 

[Tinker]

[member=550]Tinker[/member] I know it's been suggested before, but I do hope you'll write a book some day. I love your reminiscing. You bring back a lot of fond memories.

My mom and dad bought their first home in I think 1951. It was just a "shell" - exterior finished, interior not. After several months my dad had enough of the interior plastered that we could move in. I remember as a long lad watching him do all the plastering. I was too young to be of any help but I'm sure I was quite a nuisance with all the "why?" questions. Anyway, when I entered first grade my dad announced that he was going to finish off part of the basement into a family room. He finished it the year I graduated from college. My folks invited some friends and neighbors over for a christening party. Somebody said the new family room looked real nice. And my mother said " Yeah, and it only took him 15 years." And which point my dad proclaimed "Yep, finished early, and under budget, too!"

@ BarneyD,  Your dad and I would have hit it off really great.  Seems like he works on your house at nearly the same pace I have done work on our home. Some jobs  have taken 52 years to complete. When I get to be 40,  I'll retire and finish some of the projects I have started... including writing that book. Thanks for the encouragement.
Tinker

 

[BarneyD]

For the OP [member=12487]duburban[/member] , I found my grandfather's book. If you have any interest, PM me and I can send it to you if you promise to return it.  It may also be available in a local library. Not sure. It's called "Practical Plastering and Cement Finishing" by Byron Dalton copyrighted 1937. Most of what's in it is Greek to me. I've never done any plastering.

 

[peter halle]

Interesting that the 1949 edition is available for purchase out on the internet.  You grandfather would have been extremely happy if he could have gotten $74 - $82 per copy.

Peter

 

[BarneyD]

Wow. I had no idea. Yes, I'm sure he'd be proud. Both my dad and grandfather are gone but my mom is still kicking around. I'll have to mention this to her. I'm sure she'll get a chuckle out of this.
Thanks, Peter.
Barney