Cracked up: Repair old plaster carefully

3rd Generation Painters PLUS

 Q. My plaster walls are crumbling. Should I replace with dry wall or just maintain the plaster?

A. To check if you have plaster or dry wall, look, feel and knock on the wall, and consider the age of the house. In the '50s, '60s and '70s, plaster was the covering of choice for interior walls. To determine what type of wall you have, check the cracks– if there are straight lines, you have drywall. These are stress cracks and are associated with aging– they're just like the house's wrinkles. If you don't see any lines, the feel of drywall and plaster is also different. Drywall is smoother, whereas plaster has a "rocky" feel. And one last determining factor between plaster and drywall– if you knock on the wall, plaster has more of a solid sound.

The easiest way to tell, however, is to use a utility knife. Stick a quarter of the blade into the wall and turn it. If it's plaster, the wall will start cracking. Drywall does not crack. (Be careful not to do this little test in the middle of the wall.)

In general, drywall is easier to replace, repair, and remodel. It's cheaper to redo a house with drywall. To remove and replace plaster, you have to be certified. In some older homes, plaster was mixed with horsehair, fiberglass, and, in some cases, asbestos. It's very dangerous for do-it-yourselfers to tackle plaster.

To hang items on plaster walls, you need to use a molly screw. There's no way to prevent cracking, however. Look for a 2x4 or stud in the wallthis is the safest way to hang anything. Always look at the weight capacity of what you're hanging. The less weight, the less cracking in the walls. Again, homeowners must be careful with plaster walls because of the potential for fiberglass and asbestos.

When deciding to renovate your home, it's always worth it to switch over to dry wall, because your plaster will continue to wear and crack. You can either switch the walls out, or place dry wall directly over the plaster. For the latter, be sure to have very long screws, since they need to go through two layers of wall to get to the studs.

Recently, we were repairing drywall at a local home where the homeowner had tried to put up shelves with molly screws. He pre-drilled holes in the wall, but he had also cut into the waste-drain pipe. When we were called in to replace the pipe, the wife flushed the commode. With a section of the pipe missing, needless to say, we were "shi* out of luck."

Sandy Painter
PHOTO BY MICHAEL BEHR