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Repairing Plaster Board

I could post a picture, but not at home right now . . .

My house was built in 1964 (Arlington, Va) -- it's brick all around and the walls are "plasterboard". I've lived in it for about 2 years but haven't done interior work and am puzzled by the plasterboard. The boards appear to be like drywall sheets mounted to studs (most likely nailed in), and the cheap electronic stud finders are of no use, and even rare earth magnets are no use (like the "thud" finder. The magnet can find baseboard nails, but often nails miss studs.

Well, my questyion is how to patch cut-outs (I'm covering up large cavities that were cut for alarm keypads mounted to recessed metal frames; new keypads are smaller and can be mounted to standard outlet boxes). Some cavities need to be patched on the sides.

The plaster boards appear to be 7/8" thick -- boards have 3 layers -- a finished layer about 1/32-1/16" thick, a main plaster layer (gray color) that is about 2/3 pct thick, and a 1/3 back layer (eggshell white). I didn't detect if paper sandwiched the layers (paper backing of course)

I thought the thickest repair drywall is 3/4", so just looking at this and without burning gas to HD or another supply store, I am stumped on how to fill large cuts.

A. Spruce
Re: Repairing Plaster Board

Simple fix:

1 - If the metal rings are flush to the surface of the wall, then you're good to go, if they are proud they need to be removed.
2 - Cut some lengths of 1x2 as backing rod for the patch. You can either install them around the perimeter of the hole or across the opening, your choice. For anything smaller than 4" a single stick lengthwise across the opening will suffice, for larger holes two sticks or go around the perimeter of the opening.
3 - Install the sticks with drywall screws, careful not to damage the edge of the hole. Pre drill if necessary.
4 - Cut your patch material, drywall is the preferred material, to fit the opening. You can use multiple layers of different thicknesses or cut spacer shims from scrap wood.
5 - Spacer material can be "glued" in place with a dab or two of drywall compound while you are placing the finished piece. Screws through the whole "sandwich" will keep everything in place.
6 - Tape with fiber joint tape (easiest to use ) and joint compound. It will take at least 3 layers of compound to finish out the joint properly. Sand or sc**** with a drywall knife between coats to smooth and remove lumps/bumps.
7 - Texture to match as close as possible.
8 - Apply two coats of a good primer to the patched area, Zinnser Bull's Eye 123 is a good product.
9 - Apply one coat of paint to the patched area, then repaint the entire wall to blend the whole thing together.
10 - Sit back, crack a cold one, and admire your work.
11 - Repeat step 10 until you feel the work has been properly admired. :cool:

Re: Repairing Plaster Board

There are at least two approaches:

1. You can combine 1/2" drywall and 3/8" drywall together to give you 7/8" deep.

2. You can enlarge the holes to go from one stud to the next. Then attach 1x2 strips to the studs. Mount them 3/8" out, and screw 1/2" drywall into them, to the surface of the wall, tape, mud, sand, prime and paint. Viola.

Re: Repairing Plaster Board

OOPS, spruce is up early this morning too.

Re: Repairing Plaster Board

duh . . . I didn't think about 1/2" & 3/8" drywall combo or shimming . . . my public education is embarassing.

Thanks, gentlemen.

Re: Repairing Plaster Board

Cut the plaster square and follow a.spruces advice for the first 3 steps use blueboard instead of drywall. Bond the edges of the old plaster. Mix up a little structo lite plaster and pack the hole full and screed it off with the edge of the trowel. Now cut back the edge of the new plaster while its still wet so it creates a little dip at the edge of the old and let set. now apply finish as it sets trowel smooth adding water using a paint brush for lubrication . After that sets your done wait a day or two and paint. That's how I'd do it but plastering is what I do. Hope this helps.

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