If you live in an older home built before the advent of drywall, you know that old plaster walls and ceilings require a lot of maintenance to keep them looking good; they can get pretty crummy looking after years of neglect. Cracks and peeling tend to appear regularly due to settling of the house, contraction and expansion of framing, and moisture buildup in the walls.
I awoke one morning not being able to stand the peeling and cracks any longer. The choices, I knew, were: cover with a thin sheet of drywall
, skim coat the walls with plaster
, or patch up the plaster
Covering with drywall would mean covering the edges of the old baseboard and crown molding, something I didn't want to do. And I was not about to remove my handsome old moldings and then reinstall them. The moldings would surely get ruined in the process.
Nor was I about to apply a skim coat
, a process that involves covering the entire wall with a new topcoat of plaster or drywall compound. It's a difficult skill to master, especially if you're doing it only once or twice.
So I took the patching route. With it came an extra step that I believe ensures that I won't have to be doing the job over a few years from now.
Beginner and up. If you're a beginner, take care not to apply too much drywall compound. It goes on easy but is messy to sand away the excess.
Several hours or more, depending on surface conditions.
TOOLS & SUPPLIES
- Taping knife
- Concrete bonding adhesive (you can also use patching plaster instead)
- Sanding sponge
- Painting supplies (paint brush or roller, primer, and paint of choice)
Less than $20 for the patching supplies, some of which you may already have around the house. The cost of painting supplies vary according to the type of paint you choose, and whether or not you use primer.
1. First, use a taping knife to scrape down all the peeled areas and dig out loose plaster from cracks.
Run the edge of your taping knife along hairline cracks to widen them a bit. From past experience, I know this is the only way they'll have a chance to grab enough compound to disappear.
2. Brush a Quickrete concrete bonding adhesive at full strength over all of the areas you scraped.
I'd had experience patching concrete and stabilizing old mortar joints using this milky liquid (ethylene polyvinyl acetate co-polymer) with great success, and noticed on the label that it was recommended for bonding plaster to plaster, too.
3. Once the adhesive is tacky, apply all-purpose joint compound with a taping knife,
per the manufacturer's directions. You can also use patching plaster
to make repairs like this, but premixed drywall compound is a lot more convenient and easier to sand.
4. When dry, lightly sand with a sanding sponge and apply a second coat.
You can also use a clean taping knife to knock down (scrape smooth) bumps and ridges.
5. In areas where the cracks are deep, the plaster may need a third coat.
(Note: Before using joint compound, check the label or maker's web site to be certain that it is recommended for use over plaster.) For my project, I chose USG's Sheetrock brand multi-purpose joint compound
, which is fine for minor patching over plaster.
6. Before painting, coat all patched areas
with a primer-sealer formulated for use over drywall compound
As everyone who lives in an old house knows, the patches won't last forever. I'm hoping for at least a few years of a crack-free finish. Maintaining a reasonably consistent level of humidity
in your home, combined with venting of kitchens, bathrooms and attics, will help reduce problems with plaster.