Question:

My name is Terry and I live in San Diego. I am looking for a tool called a " Chicken Foot " (so I've been told) to be able to do some plaster patch work at my house. It's not a Crows Foot Brush. Does this pattern look at all familiar to you. It's in a 1931 Spanish style house. I haven't been successful in finding anyone here that is familiar with it. I found your site on the web and thought I'd give it a shot.

 

 

Answer: 

That texture does not require any special tools. Mostly just some time patience and experimenting. It is done with a sponge, dipped into the plaster, then pressed against the ceiling. When pulled away the mud lifts into peaks, it is then washed as it is setting to remove the pointed ridges. A heavily used sponge usually produces better pattern because it is not as stiff. You will need to experiment with the thickness of the mud, how much is on the sponge, how long to wait before washing. I suggest you get some drywall, and Easysand 20. Practice before you start on the ceiling.

 

 

Question:

I have a question that nobody can seem to answer for me. I work for the ........... in a historic site. We are doing some remodeling and we have a problem. Years ago canister lights were put in the museum. They are recessed so holes were cut into the plaster ceiling. We are wanting different lights and then canister holes need to be repaired. It is no problem removing the canister but what would you suggest be done to repair the ceiling and make it look solid again? I hope you can offer some solution. They don't give us the funding to have this professionally done and I haven't found anyone willing to donate this repair work. If you could give us any help it would be greatly appreciated. We try very hard to protect this 1836 building and it appears from your photos you try to do the same. Once again thanks for any help.

 

Answer: 

I try to avoid teaching plaster techniques over the Internet but since you are far from my home, I will give it shot.

 

We will keep this a simple as possible with materials and tools that you should find at Home Depot.

 

Materials List:

    

bullet

Patching Plaster , 1 bag 25-30 pounds. CreteWeld or other Concrete bonding Adhesive

bullet

1 quart Steel Lathe, Diamond Mesh.Some small wire, electric wire or even a coat hanger

bullet

Fine Clean Sand. (blasting sand, mason sand, even beach sand, - clean is important!)

 

Tools List:

    

bullet

Wire Cutter

bullet

Tin Snips

bullet

4" Drywall Knife

bullet

10" Drywall Knife

bullet

1" Stiff paint Brush

bullet

4" Soft Paint Brush

bullet

Buckets (about 2 gallon size - convenient but not critical)

bullet

If you can grow a third hand or have one attached by you local doctor this will be useful.

 

Step 1:  Remove loose or deteriorated plaster from the edges of the holes, it is good to vacuum the dust from these edges.

 

Step 2: Cut some squares of lathe about 2" larger that your hole - one for each hole. Attach a piece of wire 4 to 6 inches long to the center of your pieces of Lathe. Flex and fit into the hole so it is laying on the back of the plaster.

 

Step 3: With a 1" paint bush coat the edges of the old plaster with bonding adhesive. This is critical: bonding adhesive stabilizes any remaining dust, and prevents dry plaster from taking the water from the new plaster. If water is absorbed at the joint the cement does not properly cure, and you get a weak joint: this becomes a crack in about 6 months.

 

Allow drying time of about 15 minutes before next step. The bonding adhesive should not be completely dried.

 

Step 4: With 4" knife and bucket mix a couple pounds of plaster. Start with dry powder, add water, get out the lumps, bring it to about the consistency of peanut butter. Toss in a couple handfuls of sand. (amount? its not rocket science, it just reduces shrinkage and strengthens the mix, important since this is going on thick). You are only going to have about 10 minutes working time with this. It gets hard in about 15 minutes. DO NOT remix or try to use plaster that has begun to get hard, Throw it out. A few pennies worth of over-worked plaster will cost you all the labor of re-doing the job next week.

 

Wear your Safety Glasses. This stuff is caustic it will burn your eyes badly.

 

Step 5:  Now you are on the ladder, You have a bucket in one hand and your 4' knife in the other. With your third hand use the wire as a handle to hold you lathe in place while you pack plaster around the edges and through the lathe. Your goal is to bond the lathe to the old plaster. Keep this layer about 1/4" below the surface of the old plaster. You should be able to let go of the wire, and have every thing stay in place. At this stage it is good to be rough and uneven with the fill. Let it get very hard. 15 - 30 minutes. ( good job, have a beer or glass of wine if you are a liberal)

 

Step 6: Mix another batch. Fill your hole to 1/8" below the surface of the old plaster. Take a small piece of lathe and use it as a tool to scratch the surface of this layer. (now it's lookin' good have another beer and relax).

 

Step 7: Mix one more batch. This time NO SAND. With you 10", knife fill the hole evenly just above the surface. WAIT until it starts to get hard. Dip your soft paint brush in water, draw it across the surface of your plaster followed by your 10' knife. You are wetting the plaster and lubricating the knife blade as you are cutting off the excess plaster. Your blade should be at about a 45 degree angle with enough pressure to take off some plaster but not enough to break it up. Start with light pressure, use more as it gets harder. Tip your blade lower to fill any small holes with accumulated plaster.  (Repeat this process until the extra arm falls off, you no longer need it anyway. )  You are going to pass over it 5 or 6 times wait a few minutes and repeat, doing this process until the surface is smooth and hard.

 

Step 8: Pick up the 3rd arm, pat yourself on the back. You are probably the only one who will notice what a great job you did. Drink some more beer, wait 2 or 3 weeks paint with Kilz. Plaster is very alkaline, modern paints will not stick. This reduces as it cures over the next 2 to 3 weeks, but most paints still will not stick.

 

 

Question:

I recently had a water problem on my outside staircase wall. My house is 100 years old and is all plaster. I want it to look the same but my contractor is telling me that no one does plaster any more and that if someone would do it, it would be very expensive.

 

Do you know of anyone in Wisconsin that would be able to do my work for me? I live in Wausau (central Wisconsin)

 

Answer: 

100 year old plaster presents some special problems: Usually it is beginning to weaken as the chemical bond have broken down, the cow hairs have gotten brittle and the keys begin to fall from the backside.

 

Repairs must be handled carefully with as little shock and vibration to the walls as possible. Hair in the old plaster served to bind the plaster together, the same way that fiberglass is used in reinforced concrete. No one makes a fiber reinforced plaster, and none of the modern plasters will work on wood lathe without a fiber embedded into the plaster. Cow hair is not available since all the foundries have moved to the third world in order to avoid pollution regulations. It took me three years to find a suitable replacement.

 

Your general contractor is just ignorant. There are a lot of plasters around, you just have to know how to find them. Since USG is the nations largest supplier of drywall and plaster products, you need to find a local distributor. Usually a company that specializes in delivery of drywall for contractors (not one of the big box stores). When you find one call them and ask them who is buying plaster products.

 

Good plaster work is not cheap. Demolition and repair usually costs about $21per square foot on larger jobs, $800 per day on smaller jobs. Repairs involving wood lathe generally take 3 days.

 

I can travel to Wisconsin if you cannot find a local contractor.

 

Jim

 

 

Question:

I recently became the building manager for a 100+ year old Masonic Temple in Auburn, California. This is a beautiful historic three story building which is in need of some repairs. The building has many holes in the walls. Most of the holes were created many years ago when the old heat steam pipes were removed. There have been a few repairs made to the plaster walls over the years which look awful (bulging areas). I would like to find someone in the Northern California area who has the skill to repair the plaster holes and cracks. I have contacted several contractors to no avail. Can you give me any suggestions on finding a craftsman in our area?

 

Answer: 

You could buy me tickets to California - I don't mind traveling for interesting work! Or you could find a local building supply company that deals mainly in drywall. The major manufactures of drywall also produce plaster products. You might check the USG (United States Gypsum) for a local dealer. When you find a supplier that carries plaster products. Ask them for the names of the contractors that are buying them. Be specific about the skills you need. Some commercial contractors are using plaster to fill steel door frames as a fire stop. But this keeps plenty of fresh product on the shelf for those of us who actually repair plaster.

 

Jim

 

 

Question:

I live in Idaho. I have a hundred year old home. I have a section that my paint bubbled up due to an air conditioner leaking. I have peeled off the paint and the 4 layers of wallpaper that were underneath that I was unaware of. I was wondering if you knew how would be the best way to repair the section for painting. It is about 3 feet wide by 2 feet high. Can I put drywall on top of the existing wall? I am not sure what it is, it looks like cement. The house is made from balsic (?) rock. But the walls seem to be made of cement. Very hard to put up pictures. Any info would be great. I know it is hard to make a decision just from a description. I just need to fix this mess!!

 

 

Answer: 

Your original plaster is a mix of sand, portland cement, and animal hair. This is usually finished with thin white layer of lime and gaging compound. Todays available substitutes are USG Structolite base coat plaster lime, and gaging compound. All should be available at a commercial drywall supplier. The instructions on the bag should be followed carefully. You might also look at the USG website (United States Gypsum) Also the national park service has some good pages on the restoration of historic plasters.

 

Preservation Brief 21: Repairing Historic Flat Plaster--Walls and Ceilings

 

Good luck,

 

Jim

 

 

   

 


Copyright 2008. JPC Plaster & Drywall. All Rights Reserved.