Fixing Old Plaster Walls

Once again, He Who Hogs The Power Tools has graciously agreed to do a Guest Post for us. The topic of fixing a cracked plaster wall is one that comes up around here a lot… Just this morning, in fact, there was a lively coffee-shop discussion on the subject. Everyone around the table agreed — there’s no DIY method that compares to “buttoning it down” with plaster washers… ~ Jen

After a couple of years of trying to ignore the cracked walls and loose plaster in the living room of our 100-year old farmhouse the time finally came to tackle it head on.

I’m not talking about filling a couple of crevices with a bit of joint compound. I’m talking about full-on reconstructive surgery.

The Big Kahuna — an 8-foot canyon running diagonally from baseboard to ceiling where the plaster keys (the plaster that oozes between the strips of lath) were broken and the plaster at the edge of the crack was an inch away from the lath —was the major head scratcher.

So, what’s the best way to fix old plaster?

Drywall over it?

Remove the plaster and start over?

Both of these options seemed like a lot of work (and mess).

But mostly — this old house still has it’s original 9″ baseboards and wide, profiled moulding complete with 6″ corner blocks which we wanted to keep intact. I searched the ol’ interweb and found just the ticket — plaster washers.

These cheap little doodahs work like a charm.

How to Repair a Cracked Plaster Wall with Plaster Washers

You just slip a plaster washer over an ordinary drywall screw and drive it into the lath and studs. It snugs the plaster back to the lath as the washer flattens out, leaving you with a countersunk screw that you can crackfill over.

Step by Step:

Remove any wallpaper before you start.

Press on the wall around the crack to find where the keys are still intact — the plaster will feel solid and shouldn’t move. Poke around a bit to see where the plaster moves. Press on a spot with one hand and check the area around it for movement with the other.

Zero in on the spots that have the most effect, and drive a screw/washer. Work logically from one end of a crack to the other, adding plaster washers every few inches (or closer, as required).

As you work your way along the length of the crack, also gradually place your washers closer to the crack itself. In other words, work from the stable plaster further away first and gradually move in towards the crack itself.

Don’t be shy. Use enough screws and washers to make sure the plaster isn’t going to move. (I used over a hundred of these plaster washers to tackle that crack I called The Big Kahuna.)

Fill any large holes in the plaster with pieces of drywall screwed to the lath.

After the plaster is buttoned down, clean any loose plaster from the crack. An old can opener (the kind we used to use to punch holes in cans before pull-tabs) is great for cleaning out the crack to accept joint compound. Use a heavy-duty joint filler like Durabond 90 which is made for large/deep cracks. (This stuff is hard to sand so use it in the deepest cracks to rebuild a solid base.)

Finish to the final surface with drywall tape and a couple of applications of conventional crack filler until you’re happy with the results.