In older homes, it’s not unusual for the original plaster on the walls to crack and weaken over time. As the house settles and walls move slightly, the bond between the plaster and the lath—the supporting wood framework—can be broken, and the plaster begins to pull away and eventually crack and crumble. There is now a way to repair the damage: Big Wally’s Plaster Magic, a plaster repair system available at Boston Building Resources.
Repair has several advantages over the expensive and dusty alternative of removing the plaster and replacing it with gypsum wallboard. Repair is less expensive. A homeowner can do the work using common tools. Repairs can be made without the major disruption that replacement can cause. Waste is reduced or eliminated by conserving the original plaster. And you will keep in place a historic building material that is longer-lasting than gypsum wallboard.
Plaster Magic stabilizes weakened plaster by reattaching it to the lath using a two-part system: conditioner and adhesive. First, holes are drilled on either side of the crack and dust vacuumed out. Then, conditioner is sprayed in; this removes remaining dust and prepares the wood lath to receive the adhesive. Next, a specially formulated adhesive is injected into the holes, and clamps are inserted, tightening the contact until the adhesive can cure. Then, the clamps are removed and the holes filled with joint compound, and the surface sanded and finished.
Vermont contractor Rory Brennan developed Plaster Magic after searching for, and not finding, a plaster repair product that was designed to last for the long term. “When it comes to repairing plaster, I want to fix it so it lasts,” says Rory. “I want the results to last as long as the life of what I’m fixing. For plaster, it’s a multigenerational material.” Thirty years of experience fixing plaster have given him many opportunities to test materials and methods and to discover those that do and don’t work. Through experimentation, he formulated the conditioner and adhesive system to work especially with plaster.
Rory taught a plaster repair workshop at BBR in June, patching up a damaged ceiling and wall at the Spontaneous Celebrations building in Jamaica Plain. In settings like this one, where the plaster was not only cracked, but had areas of bare lath where the plaster had crumbled away, a patching plaster can be used to fill in the voids after the edges of the damaged area have been stabilized.