How to Repair Hole and Cracks in Plaster Wall
Plaster, which is applied when it's about the consistency of wet cement, stays in place by oozing between lath of wood strips or, in houses built after about 1930, perforated wallboard or . After oozing through gaps in the lath, the plaster slithers pathway down the back of the lath to form what are called keys, really a grip like curled fingers on the lath's back side. water damage, vibration, or settling of the house can cause keys to break away from the face of the plaster. That leaves the plaster loose; it will eventually fall out and leave a hole. metal mesh
Often, cracks do not include separation of the face plaster from the keys. Fixing these cracks are relatively easy, which we will discuss first.
To make sure cracks do not reappear after repair, identify their cause. If you summarize that the house is settling or the framework is spreading apart, you must solve the problem first; otherwise, the cracks will reappear. Other movements that have caused cracks also must be remedied if a repair is to last.
Once the causes of cracks have been repaired, treat the cracks like seams in drywall rather than widening them by undercutting and then patching with plaster.Instead of using paper tape use fiberglass mesh self-adhesive backing tape.
Clean the cracks of dirt and dust, and then apply the over cracks. although fiberglass tape is slightly thicker than paper tape, it has two advantages. First, it allows more flexibility than paper tape, meaning the wall can move some more before a crack reappears. Second, unlike ordinary drywall paper tape, fiberglass mesh tape does not require a coat (which is called the bedding coat) of drywall joint compound to hold it in place. fiberglass tape
Once the fiberglass tape is in place, cover it with joint compound using a wide trowel. Even if you do not want to do the repairs yourself- and with fiberglass rather than paper tape, the repairs are much easier for an amateur the method makes a durable repair and is worth requesting from who will be doing the work.
To repair holes in plaster, first examine the extent of the damage. If the holes are less than six inches, across and the wood lath is sound, allowed use patching followed, when dry, by a top coat of drywall compound. An alternative method is filling in with drywall. First make the hole a regular shape, usually a rectangle.
Then, cut the gypsum portion of a drywall board into a patching piece of slightly smaller dimension than the hole that you have cut open leave the paper portion of the patching piece larger than the hole. however, by about 3/4 inch all around.
Cut this way, the gypsum portion of the patching piece fits neatly into the hole, and the paper portion laps onto the plaster. The paper is then covered with joint compound.This type of patching is also suitable for repairing a drywall-covered wall.
If the hole is larger than six inches on a side, definitely repair it with drywall instead of plaster. again cut the hole to a regular shape, preferably to the studs on either side. if the plaster feels loose around the hole, use drywall screws and plaster washers to hold the plaster fast against the lath.
Cut the drywall to the same shape as the hole about 1/4 inch smaller all around the hole's edges there is no need for a paper flare around the hole if the if the patching piece is going to be nailed to the studs. If the drywall is significantly thinner than the plaster, glue or screw wooden shims onto the wood lath to make it flush with the surrounding plaster. Fasten the drywall to the studs with screws, cover the joints between the drywall and plaster with fiberglass tape, then cover the tape with joint compound.