I’ve written about repairing plaster walls before, but sometimes there are sections of plaster that have been removed or are missing and you need to fill in the gaps. I’ll show you how to easily fill in these missing sections.
This repair also works on drywall for all you new house folks too.
When you have an area (large or small) where you’re missing plaster, whether it’s thanks to the electrician/plumber/HVAC guy or the plaster was damaged some other way, you can patch the area rather simply with just a few items.
- Scrap wood
- Driver or drill
- Drywall screws (varying lengths)
- Drywall or plasterboard (varying thicknesses)
- Drywall knife or trowel
- Setting type joint compound or plaster
If there is still lath in the damaged section, then the repair is even simpler, but that’s not always the case. If you do have lath behind the void, then skip to Step 2.
How to Patch Plaster
Step 1 Install Supports
If you have a hole (like in the picture) the first thing you need to do is attach support pieces. These supports are just small pieces of scrap wood (1/2″ to 3/4″ thick) that you can attach the patch to.
Cut at least 2 pieces (cut more if there is a large area to patch) a few inches longer than the void you have to fill. In this case, I had a hole that was 4″ x 5″ so I cut 2 pieces of wood 7″ long.
Next, slip them into the void and lay them across the opening as you see in the picture. These will be the supports for a piece of drywall or plasterboard we’ll install shortly.
Once you have them in place, attach them with a couple screws into the existing plaster. Make sure to use screws long enough to make it all the way through the plaster and support pieces.
As you screw in, the support piece may be pushed up by the screw. Just back the screw out and try it again. It may take a few times to get the screw to pull the piece tightly to the backside of the plaster, but it will work.
Sink the heads of the screws into the plaster and don’t leave them proud of the surface, you’ll be covering them later.
Cut a piece of drywall or plasterboard the same size and shape as your void and attach the piece using drywall screws. Screw the patch into the support pieces (or lath) every 6-12″ so that the patch is securely in place.
If you’ve got a complicated and large area to patch, you may have to be a bit of an art student to cut a patch to match, but just do your best. You can always use multiple pieces if you need to.
Step 3 Get the Right Thickness
Depending on how thick your plaster is, you may need differing thicknesses of patching board. For thick plaster, I’ve used 2 pieces of 1/2″ plasterboard stacked on top of each other. Other times it’s a piece of 1/2″ and 1/4″ board. In this case I got away with just one piece of 5/8″ plasterboard.
It really depends on your wall, but the important thing is that the patch should be just a little shy of the thickness of the wall. You don’t want the patch to be the same thickness of thicker than the wall, otherwise it will be visible later.
With this technique, you won’t have to make a big sanding mess like with other patches.
Use either veneer plaster, setting-type joint compound, or my favorite Big Wally’s Patching Plaster for the repair. Mix up a batch and cover the patch and screws so that it is just a little proud of the surface of the existing plaster.
As the compound firms up, wipe it down with a damp sponge so that the patch is now completely flush with the surrounding plaster.
Step 5 Add Texture
Depending on whether your wall is textured or not, it’s now time to add the final touch. Whether it’s an orange peel, knockdown, sanded finish or some other type of texture, you can now add that texture to the wall as best as you can to match the existing style.
I’ll be posting next week about some of the most common plaster textures and how to match them.
I hope this encourages you to patch your plaster walls and not tear them out. It’s not that difficult to patch plaster and with a little practice, you will never even see the patch. Plaster really is a better wall material than standard drywall and it deserves to be saved.
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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.