Lathe and Plaster Repair

Small cracks up to ¼ inch wide, on secured plaster walls and ceilings, use a blade (I use my 5 in 1) and “V’ or groove the crack and remove all loose plaster and dust. A suitable repair would be to use joint compound, (I use 20 minute or 45 minute Lightweight setting type, with a plaster ad-mixture mix for bonding and strength) Be cautious sanding on old plaster as there are possibilities of lead and asbestos.

If pieces are missing and you can see the lathe, remove all loose plaster around the edges. If the surrounding plaster has lost some “keys” (cured plaster folded over lathe) use screws and plaster washers to attach back to lathe. Insure the lathe is still attached securely to frame work. Wet the lathe with water sprayed from a bottle or brush on the water. I do my first coat (scratch) with Structolite plaster that is mixed with perlite. It is lightweight and sets quickly and hard. This is used to re-key to the lathe and to give your next coats something to adhere to. My second (brown) coat I would use the same setting joint compound as mentioned in the above paragraph insuring it troweled level and butting up with the old plaster. Again, wet the area with a mist of water, including the old plaster edge. Finish off with a thin layer of same plaster to the level of the old, sand and prime.

To be more correct historically, you would mix lime putty with sand mix for the scratch and brown coat and your finish coat would be more of a fine lime troweled on to match the texture. For preservation purposes the old plaster should be analyzed for sand/lime ratio and other ingredients.

Some like to just screw in drywall in the missing area and use joint compound to finish. I prefer to replace it as it was.


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			Lathe & Plaster Repair
			Small cracks up to ¼ inch wide, on secured plaster walls and ceilings, use a blade (I use my 5 in 1) and “V’ or groove the crack and remove all loose plaster and dust. A suitable repair would be to use joint compound, (I use 20 minute or 45 minute Lightweight setting type, with a plaster ad-mixture mix for bonding and strength) Be cautious sanding on old plaster as there are possibilities of lead and asbestos. If pieces are missing and you can see the lathe, remove all loose plaster around the edges. If the surrounding plaster has lost some “keys” (cured plaster folded over lathe) use screws and plaster washers to attach back to lathe. Insure the lathe is still attached securely to frame work. Wet the lathe with water sprayed from a bottle or brush on the water. I do my first coat (scratch) with Structolite plaster that is mixed with perlite. It is lightweight and sets quickly and hard. This is used to re-key to the lathe and to give your next coats something to adhere to. My second (brown) coat I would use the same setting joint compound as mentioned in the above paragraph insuring it troweled level and butting up with the old plaster. Again, wet the area with a mist of water, including the old plaster edge. Finish off with a thin layer of same plaster to the level of the old, sand and prime. To be more correct historically, you would mix lime putty with sand mix for the scratch and brown coat and your finish coat would be more of a fine lime troweled on to match the texture. For preservation purposes the old plaster should be analyzed for sand/lime ratio and other ingredients. Some like to just screw in drywall in the missing area and use joint compound to finish. I prefer to replace it as it was.

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