Back in the 1900s, interior walls were mostly covered with plaster, because drywall did not yet exist.
The plaster was most likely applied onto horizontal strips of wood, called lath, and as it oozed through the spaces on the backside, it dried. The excess plaster hardened into the firm foundation that holds up the remaining layers.
Depending on the age of your home, you may have to repair your old plaster walls. It’s best to hire professional painting services that will handle correcting each plaster problem in the proper way.
Homes with old plaster walls will begin to crack over time. Some cracks are caused by a direct impact, but most happen due to high humidity or the house settling. Both hairline and large cracks need at least a skim coat of drywall joint compound to start.
Your painting contractor should apply a skim coat of compound over the crack at least 8 inches out in all directions. This skim coat acts as an adhesive for a sheet of fiberglass mesh. With more compound spread over the mesh, the crack will be hidden and it will make the plaster look smooth.
Holes or Crumbling
Direct impact, such as a doorknob hitting the wall, can create significant holes in the plaster. Crumbled plaster happens when there’s poor workmanship, not stress, house settling or impact. Crumbled plaster requires removing the damage and patching empty spaces.
Your painting contractor knows the only way to deal with crumbling is to scrape or brush off loose plaster to reveal the lath underneath first. Then they will patch the bare spot with drywall by screwing it back into the lath.
Old plaster walls have imperfections that are part of their charm. Sometimes walls weren’t built up with thick enough plaster layers, which leaves evidence of the underlying lath visible on the surface. This will create horizontal depressions across the wall at the location of each space.
With a bit of investigation, you can find the low spots and fill them in for a smoother, flatter wall. Your painting contractor will lay a straightedge against the wall to find the dips, and spread plaster refinishing compound over them using a flat trowel.
If you have old plaster walls and they need repair or just a fresh coat of paint, contact us for an estimate – we’ll be glad to help you make the old plaster walls in your home look like they should!
Have an old home with textured walls? Check out our blog post on smoothing textured walls for tips on doing just that!