How To Repair Plaster Cracks

Dealing With Old Or Damaged Plaster
By Edwin Brown

Old ugly or damaged plaster -- what a turnoff!

That old house may have tons of charm, but when the plaster is a disaster, you have a real problem on your hands.

The good news is, it is fixable in most cases. And when the plaster is just too far gone to repair, there are other remedies, like overlaying with drywall, or getting a contractor to replace the plaster.

But I want to focus on plaster repair. Yes, with some instruction, motivation and dedicated application, you can deal with old plaster and restore the beauty it once had. And you can do it without using any plaster!

Despite what you may have heard, it is possible to do a very nice repair and renovation job on old plaster walls or ceilings using drywall finishing materials. I have done hundreds of projects over a 35 year period. It works --if you do it right.

For cracks, you need to do a lot more than the old finger and spackle trick.
Drywall paper tape provides the strength to bridge the crack and keep it from reopening. Treat each crack like a drywall joint. Tape, two coats topping, sand tool marks and edges, and texture back in to match.

When there are lots of cracks on a wall or ceiling, treat them all then skim out the remaining surface and texture the whole thing. Texturing is a lot of fun and gives you a chance to be creative. I have developed a number of unique and fun textures over the years. Practice on scrap drywall to get the feel of what you want to do.

Small holes and dings can be filled with "hot mud", a setting type of joint compound that is tougher and harder than regular joint compound. Hot mud, by the way, is superior for taping and topping purposes also, but trickier to use because there is limited time before it hardens. So I would recommend the longer timed bags, like sixty or ninety minutes.

Small holes may require two or more fillings before they are level. Larger holes, if the wood lath backing is still in place, can be filled with thin drywall and then taped around the edges and skimed with as many coats of joint compound as necessary to bring the whole patch level with the surrounding plaster.

If no backing is present, you will have to provide it using boards or plywood and drywall screws. Then put in drywall to fill the hole. You may have to attach some kind of shim material on the backing so your drywall will be level with the plaster after you fasten it to the backing.

It is essential that you prepare the surface properly before you start the repair. You need a clean, tight surface to work on if you want your repair to be permanent. Remove all dirt, loose material, and dust. On water-stained areas, scrape or wire brush, wipe clean, then apply a stainblocker.

When that is dry, proceed.

It is often advisable to roll on a bonding agent over the areas to be repaired or skim coated, to insure a good tight bond.

There is no thrill like standing back and admiring your work when you are all done. Good luck!