One of the easiest mistakes to make when renovating a historic home is to tear down the old plaster walls and replace them with modern drywall and joint compound. This not only destroys the historic architecture and features that make a historic home great, but it also adds to the overall costs of the project exponentially. Despite the rumors you can repair old plaster yourself.
Lime plaster has been in use for thousands of years from Japan to Egypt and has been employed in many historic structures around the globe. Lime plaster is a far superior product than today’s modern wall coverings. With its crystalline structure, it repels moisture well while allowing for the contraction and expansion that often occurs in older homes during changing weather conditions. In fact, as the plaster’s structure calcifies (ages), it increases in durability and strength!
A Little History First
The scientific service hausarbeit schreiben lassen studied the history of this material and wrote a dissertation where we can read a little history. Traditional lime plaster was used for wall coverings until WWII. It was applied in a 3 coat process over thin wood furring strips called lath that were made of cedar, cypress or some other rot resistant non-staining wood and attached to the studs. The lath was soaked in water prior to installing the plaster to prevent it from sucking too much water out of the the plaster too quickly and spaced similar to the above picture with room between each piece for plaster to be pushed thru when applied. This spacing allowed the plaster to “key” in the lath and gave it extraordinary holding power when done properly.
The plaster was then applied in successive coats, typically 2, and a smooth finish coat was applied on top. Plaster took weeks to dry properly and fully cure before the walls could be painted. The whole process was slow and required a skilled plasterer which cost more money. After WWII, the building industry needed a faster way to cover walls and the relatively new product, drywall (getting its name from the fact that it didn’t go up wet like plaster), slowly crept into everyday use.
The Repair
- Assessing – There are many reasons for lime plaster to fall into disrepair. Knowing the cause of the damage is crucial to applying the correct solution to the problem. From water damage to vibrations from nearby traffic to peeling paint, historical plaster damage can be caused by many problems. Is the plaster peeling from the lathe? Is the plaster soggy or crumbly? Are new coats of paint peeling from the walls? If you answered yes to any of these questions; don’t panic. While each condition is unique to each situation, lime plaster can be repaired easily, economically and effectively. A common occurrence in older plaster, cracks are commonly caused by expansion and contraction of an exterior wall. In the case of heavy cracking, it is possible to that the house it settling improperly. This should be inspected by a Building contractor or structural engineer immediately! Repairing small cracks is the focus of this article though.
- Dealing With Cracks – This repair can be done by drilling several small pilot holes in the materials at various intervals. By measuring the depth of the penetration, you can determine if the lathe is detached. Many times a few well-placed screws can draw the lathe and plaster back together. In extreme cases of detached lathe, more holes are drilled into the affected area and an elastomeric adhesive is injected between the separations. Clamping washers are then applied to the surface of the plaster to press the loose plaster back tightly against the lathe and allowed to dry. Once the plaster is secured, the holes and cracks can be filled flush with a mixture of lime and gypsum, allowed to dry and then painted. Check out my video on fixing cracked plaster to learn how to do it yourself!
- Peeling Paint – Another common dilemma when dealing with older homes is peeling paint, and it can be repaired with just a few simple techniques. More often than not, peeling paint occurs when many layers of paint have been applied to the plaster over the years. Calcimine is the common culprit of many peeling paint plaster problems. Calcimine is a water soluble paint material that was typically used in older paint products. The calcium in the paint reacts with the moisture content of the calcium in the lime plaster and creates a bond between the water molecules. This bond easily allows water to slip in and out of the paint’s surface, so even if you apply new paint, it peels over time. To remedy this problem, the old paint must be removed. A wallpaper steamer is the perfect tool for removing old paint from lime plaster. Gently use the steamer and a plaster knife to remove the paint without gouging the plaster. Once you’ve removed all of the old paint, wash the plaster with a rag and room temperature water. Don’t get the walls too wet; a light wipe down will suffice. Allow the plaster to dry 24 hours before repainting.
- Patching – Patching plaster in anything more than small amounts is something best left for the pros, but if you are a brave DIYer then you can try to tackle the task on your own. Old plaster is made from much different materials than current drywall joint compound. For decent sized holes the best thing to use for repairs is called Big Wally’s Patching Plaster. You simply mix with water and apply. Once your plaster is mixed apply it with a putty knife and press it firmly into the supporting lathe. Make sure the plaster isn’t sagging in the hole. If so, your mix is too watery and you should add more plaster until it is firm enough to hold under its own weight. Once the plaster has dried, give it a light sanding to smooth out the surface and wipe it down with a damp rag before painting.
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While some damages can be easily repaired, it’s easy to quickly get in over your head when it comes to plaster repairs in a historic structure. Plaster work is an art form and many delicate cornices, crown molding and ceiling medallions were sculpted by hand by skilled craftsmen. So, before you rip that old plaster down to insulate and cover with drywall think twice. You might have a unknown work of art on the walls or ceiling of your home that deserves restoring.
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I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.
I know its kinda hard to be repairing old plasters but your article just change it all. Really informative thank you for sharing.
I have moisture damage in a plaster ceiling. We have what can be best described as a “snow flake” condition. Need ideas and thoughts on repair options.
I just had a basement put under my 1862 antique farmhouse and some of my plaster walls literally buckled and fell off due to the leveling. It was off by 4 inches! Regardless, I am heartsick about the destruction and my contractor is repairing my guest room this week. My carpenter wants to put up wall board and insulate and I need to discuss who this other workman is that my contractor has. Thanks for printing this article. At least I’ll have a better idea of how my walls should be repaired.
Hi Sara,
We are so sorry to hear that that happened to you. Maybe you can find a certified preservationist in your area using our directory that could work with your GC on accurate and careful, historically accurate repairs to your home? Best of luck to you. https://thecraftsmanblog.com/directory/
-Alyssa at The Craftsman Blog
We just purchased a home built in 1692…yes, you read that right. The walls aren’t drywall. The walls are made up of some sort of thick grey material that crumbles quite easily. We haven’t dug underneath this outer layer to check (as we don’t want to destroy the walls) but, is this lathe and plaster…or something else?
It’s probably cob, an old building material that is basically dried mud made into un- fired “bricks”. Sometimes straw or animal hair was added as a binder. The material is breathable but susceptible to extreme damp. If it gets too wet it reverts to mud! The walls were most likely lime plastered on the inside and rendered with lime render outside. The exterior render would have been “waterproofed” with added casein or oil (linseed) or whatever was to hand. Whatever you do, don’t try to use modern cement-based plaster in an attempt to waterproof it: that just traps damp in and it will destroy it. Keep it breathable by using lime plaster/render and paint with a breathable paint (clay paint etc). If you do that it will last another 300 years. If you use “modern” building materials it will fail and cost a fortune to put right. Enjoy living in a house cherished by generations and remember it is fundamentally different from a modern dwelling.
Considering how common plaster is in most homes it really is a good idea to learn how to repair it. I particularly like that the article goes over how you can patch plaster if you’ve encountered any larger holes. Of course, you’ll want to make sure that you have the proper repair supplies, but once you do you’ll at least know how to carry out the repair job.
Tom Silva usually reattaches lath with screws and metal washers before attempting a repair.
I would just like to say with plaster lathe on old homes it is forever cracking. The upkeep is never ending. That is why dry wall is an option. Moldings can be repkicated. I spent 2 months restoring plaster moldings and excessive cracks on a ceiling. The job was completed 9/16. I already have a new fineline crack that appears across the ceiling. These historic buildings expand and contract all the time.
Our New England Victorian was built circa 1893. The plaster ceiling in the grand entrance seems to have been covered by some sort of fabric (mesh?) then plastered again? My husband cut the plaster and fabric as it was uneven with the rest of the ceiling and now you can see where the ceiling is smooth due to the removal of the fabric and plaster. Is there a place to purchase this fabric/mesh that we could help rejuvenate our plaster ceilings? Huge thanks!
i wonder if it is this: https://www.abatron.com/product/nu-wal-plaster-restoration-system/. I have a house built in 1876, all plaster and lath. It had had some serious settling issues, diagonal cracks in many walls. This system worked well for me. The more painted over it is. the more the matt disappears, but at the moment, I have a wall with visual texture similar to suede. JUST REMEMBER this is fiberglass, so suit up, wear a mask and glasses.
My husband and I own a tiny 1924 bungalow and water damage (due to negligence on the part of our warranty company not responding to our reported leak for a full week) was just discovered in our living room. We have a very unusual (and beautiful) rough plaster texture and they are tearing out huge pieces of my walls. I am heartsick. I am also worried that they will not be able to restore it to “pre loss” condition. I want to cry. They commented when they walked in that they’d never seen walls like ours before. This makes me incredibly nervous. Is it reasonable to expect that this can be restored to a point the repairs are undetectable? Ugh.
My husband and I just bought an old farmhouse built in the early 1930s. It is our intent to keep as much of the original character as we can, but the plaster in the kitchen seems to be too far gone. There are at least 20 cracks in the walls, some large, some small. How do you decide when the plaster is too far gone?
Hi! We are looking to buy a house from 1887 with plaster walls inside. We are hoping to update the home a bit, and a main concern is the electrical is currently outside of the plaster, running in tubes around the baseboards in each room with outlets every here and there. Everyone is telling us to remove the plaster and put up drywall so the electrical can go inside the walls, and because they say its easier than constantly repairing the plaster’s cracks and holes. But I also worry removing the plaster will damage the bricks and stone the home is made of.
What would you recommend? Is there a way to get the electrical inside the plaster walls? Or would it be easier/cheaper to put up drywall? Thank you.
I own a 1963 South Florida home, that has plaster walls, upon removal of baseboard in one of the bedrooms the thin top coat of plaster/paint is peeling up. I think I could easily use a flat blade and run it up the walls and all the top coat would come right off. After reading your article I am thinking, the numerous coats of paint has caused this. I really do not want to remove the top coat on all four walls and would like to “patch” the area that is already gone. What should I use? I have read a few things and joint compound seems to be the most suggested, but that doesn’t seem right to repair plaster. They are two different animals, correct?
Hello, My house is also lath and plaster, 1924 era. The bathroom also had plaster of paris floors covering the hidden claw foot tub. They gutted the bathroom took out the tub, refinished it and added another plaster of paris floor. Primed it with latex primer, let it dry, then the painter did a coat of floor paint ben moore, but i think what happened is he didnt let the first coat dry enough, he waited four hours is that long enough, temps were probably 65. They trouble is the paint is peeling, i dont know what to do next everything has been put back in , vanity etc. Thanks for your help
I know this is old but i was curious how this turned out. Not sure if i read this correctly but if i did then my guess was it was painted too soon. Anytime you plaster you should wait a minimim of 4-5 days before painting. I suggest waiting longer like 2 weeks but this cant be done sometimes. Most of the time i dont have an issue but it sucks when you do. Since you said it had beem primed my guess is the plaster had not dried completly. Even though plaster is dry to the touch after about an hour there is still moister that needs to be released. You can sometimes feel it just walking in the room. Also the plaster will still have a darker hue to it. This can be overlooked by someone who has no experience but the plaster will turn a brighter white when dry. If it looks brown then its absolutely still wet. You could also take a moister meter to it if unsure. Ive never had an issue afrer waiting 10 days. Sometimes i wait longer if we are having high humidity which happens a lot in Boston during the summer.
Im a plasterer full time that paints on the side. Ive been painting since i was like 14 and our parents gave us free reign over our rooms. We would need to supply our own paint and supplies though. Over the years I had done numerous paint jobs for friends and family. It turns out i was pretty good at it. The funny thing is my brother and sister are also very good painters. One part is from practice as teenagers and the other is a family trait.
We are all pretty anal when it comes to this stuff and strive for perfection. If we are going to take on a job its all or nothing. When it comes to painting we can only work alone or with each other.
With access to youtube ive been able to learn a lot of helpful tips. However i would still like to work weeknds with a pro for a while so i can learn how to speed things up.
Since ive become a plaster ive had access to a lot of painting jobs if i want them. If work is slow or its for a friend or bosses friend i will usually do it. I always try and tell people that you can have the best plastering in the world but if you hire a shit painter or do it yourself in some cases it wont matter. I hate seeing a job ruined because the painting was done incorrectly. Also ive been on jobs were plastering\ compounding was bad and no attempts were made to fix it before painting again. Sometimes its no the painters fault but when your getting top dollar and you dont have a tub of compund and a putty knife with you then your just a crook. Ive run into this recently so its been on my mind.
The point of my rant was that you get what you pay for and always check references. Like i said if the plasterer is good and the painters bad its going to show. This goes the same for a bad plaster job. Most painters can work miracles but its not thier job. Any new plaster work should require very litle prep before paint.
I am a new homeowner of a house built in 1911 in WI. The plaster walls are just riddled with cracks, some that are only a couple inches long others are a couple feet. How do I know if a crack is just too large to be repaired as shown in your video? and can you also use the shown method on ceilings?
I am adding a door in a large existing opening in my plaster wall. I carefully removed the 5 1/2″ trim around the opening and the plaster underneath is in ok condition, but a little crumbly here and there and maybe 1/16″ off in depth from the rest of the wall. My plan is to fix the wall to the rough opening and then frame out the opening to fit the door. I’m going to use drywall for the new wall section, but to fix and even out the 5 1/2″ area around the original opening where the trim was, do I need to use plaster? or would drywall joint compound work?
For a small patch like that you may be fine with joint compound. Just try to match the texture as best you can.
I have an old 1920s mortar bathroom. I excavated an opening for a shower niche, then repaired the area around the box with Plaster of Paris. Then Redgard (2 coats) over that, then tile. Was this ill-advised? I know gauge plaster isn’t rated for wet areas, but the area behind the wall has a vent and good circulation. So far everything is holding up.
Gypsum plaster is not a good idea in wet areas. You may have trouble in the future but the redgard will definitely help. I would have used modified thinset for the niche and then redgarded that.
I need to smooth out plaster/lathe ceiling and walls and some cracks and holes. I know now to use spackling. I don’t know what is the best product to use. Can you advise? Also, I read about Gardz primer as being a good primer for plaster. Anyone have experience with this? Any input appreciated
For small cracks sparkle works well, but to skim coat a whole wall you’ll need veneer plaster. I like a good latex primer for cured bare plaster or spackle.
Thank you Scott for your input. I have read that plaster patch for holes and pressure cracks works best. Are you familiar with that? Do you know kanything about/ or have experience with Zinnser Gardz?
Haven’t used Zinnser Gardz, but I do like their other products. Usually for cracks we dig out the hole a big more and then fill with spackle if we aren’t skim coating the wall. Or we filled with a mixture of veneer plaster and joint compound if we plan to skim coat the wall.
We live in a 1926 house all plaster ceilings and walls. The fireplace is also plaster with brick underneath. We had a small earthquake about 10 years ago. Since the earthquake where the fireplace meets the floor about every 8 months or so small bubble like protrusions develop and some flaking, we have been just sanding and repainting. We were told this was caused from the bricks that shifted during the earthquake letting water leak in but we have always had a chimney cap. Is this something we should be worried about or just keep sanding and repainting?
Hi John,
Congratulations on owning a beautiful plaster home. Suggestion: check where your roof meets the fireplace. I suspect the earthquake may have created a gap where water is seeping in. Try resealing the roof to the fireplace & see if this helps. Let us know…
Thank you for writing this article, I have learned much from it.
I am considering purchasing a home built in the late 1800’s to early 1900’s. It has lath and plaster walls. The thing that bothers me is that though painted nicely, for some reason the walls have the appearance of having been painted hundreds of times. I am wondering if this is because the plaster appears to be textured on the walls. I am wondering if this is the way that plaster walls always look or if this was a technique used on them. Do you have any suggestions for giving the walls a fresher look? Thanks for your thoughts.
Maralee, likely they are textured walls (likely a sand or perlite texture) that has been painted multiple times. They can be skim coated with a smooth coat of veneer plaster if you want to change the look.
In the oldest section of our historic home, the stucco was removed from an exterior wall and the stone was pointed. Inside that wall, between the corner of the inside room (the kitchen) and the outside door, the plaster has shed it’s paint and the top layer of the plaster has turned to powder, constantly shedding plaster powder. Several people have tried to repair the plaster inside and to waterproof the outside with no luck. Any ideas?
Just cover the entire wall with sheetrock and paint the sheetrock.