With all the loose old plaster removed, use a flat trowel to coat the exposed lath with plaster base coat, being sure to work the material into the spaces between the lath. In this video, This Old House host Kevin O’Conner shows you how to patch holes in plaster walls. If the lath behind the old plaster is sound, patching is a matter of troweling on layers of mud. How to Patch Plaster Walls if the Lath is in Good Condition The patch is now ready to prime and paint. On the third day, spread another coat, and after it dries, smooth it gently with a damp sponge. Gently scrape it smooth and apply a second coat. Using a 6-inch taping knife, scrape the patch area smooth, and cover the patch with a thin layer of ready-mix joint compound. How to Repair Lath and Plaster in 6 Steps 1. It’s a common practice to replace missing plaster with a piece of blue board (a wall board made to be coated with plaster), but troweling on base coat is faster. Finish coats came after the base had dried. Several coats were applied, the first keying into the spaces between the lath to make a stable base. Into the 20 th century, plaster was applied over wood lath spaced half an inch or so apart over the studs or ceiling joists. If the lath is in good condition and you need to repair holes, patching is a matter of troweling on layers of mud. Don’t use so-called patching plaster sold at home centers, it’s much harder than the wall’s original plaster, and it sets in the blink of an eye. It’s better to use a softer, slower-setting lime-based plaster, like the one developed for Big Wally’s line of plaster-repair products, takes about an hour to set, isn’t prone to cracking or delaminating, and needs no sanding, which keeps dust to a minimum.
How Do You Repair a Hole in Lath and Plaster Walls?įor lath and plaster repair, it’s important to use good techniques and the right materials. First, you’ll repair the lath and then patch the hole. If you’re dealing with damaged lath and plaster walls-for example gaping holes in the wall because of electrical work-here are techniques you can use to repair them.