How To Tell If Wall Is Drywall Or Plaster

Most people in Western Mass don't think about what their walls are made of until they try to hang a heavy mirror. Then they either find a solid surface or a hollow one that crumbles like chalk. If you are planning a renovation, you need to know which one you have.

Simple Tests You Can Do Right Now

The Push Test

Drywall is basically a sandwich of paper and gypsum. It has a little bit of give if you press on it firmly between the studs. Plaster is rock hard. It is a mixture of lime, sand and gypsum applied over wooden slats called lath. If you push on a plaster wall, it won't move at all. If it does move, it means the plaster has detached from the lath and you have a bigger problem on your hand,

The Pin Test

Grab a thumbtack or a small finishing nail. Try to push it into the wall in an inconspicuous spot. If it goes in easily with just your thumb, you are looking at drywall. If the pin bends or you feel like you are trying to drive it into a sidewalk, it is plaster

Knocking Test: A Simple Method

One of the easiest ways to determine whether your walls or ceilings are made of drywall or plaster involves using a knocking test. Gently knock on the surface with your knuckles or a similar object. This method will produce distinct sound differences between the two materials.

If you hear a hollow sound, it is likely that you have drywall. Drywall is typically thinner and has a hollow cavity behind it. Conversely, if you hear a more solid sound that resonates without much echo, chances are you are dealing with plaster, which is thicker and applied in multiple layers.

Visual Inspection and Other Tests

Along with the knocking test, visual inspection can provide important clues. Plaster tends to have a textured appearance and may show signs of cracking or peeling due to age. It is often a bit uneven, giving it a distinctive old-world charm that is difficult to replicate with modern materials.

On the other hand, drywall typically has a smoother finish and can be painted easily. Look closely for seams between panels of drywall, as these may be visible. If you see nails or screws holding the panels together, you've most likely got drywall.

You can also check the edges of outlets or switches. If they are flushed into the wall surface, it is more likely to be drywall. If they appear to be protruding and the surface is thick, then plaster is the most likely material.

Check the Calendar

The age of your home in towns like Holyoke or Northampton is usually the best giveaway. If your house was built before 1940, it almost certainly has plaster walls. Builders didn't start using drywall as the standard until after World War II. Homes built in the 1950s sometimes have a hybrid called rock lath (which is a small sheet of drywall with a plaster coat over the top).

Look for the Clues

Find an outlet or a switch plate and take the cover off. Look at the edges of the wall material. Drywall will look like a uniform gray or white slab about half an inch thick. Plaster will look messy. You'll see layers of rough material and you might even see the edges of the wooden lath strips behind it.

Why This Changes Your Project

You cannot treat plaster like drywall. If you try to fix a crack in a plaster wall with standard joint compound and a piece of mesh tape, it will crack again in six months. Plaster expands and contracts differently than modern materials.

We see a lot of DIY disasters where people try to modern-up an old home by slapping drywall over the top of failing plaster. This just hides the rot and makes the wall even thicker. That extra thickness ruins the look of your door and window trim. If you are not sure what you're working with, give MrWalls a call. We will tell you the truth about your walls and what it takes to actually