Can You Drywall Over Plaster Walls?

If you live in a home built before the 1950s, you likely have lath and plaster walls. While they offer great soundproofing and a certain historical "soul," they are also prone to spiderweb cracks, sagging, and the dreaded "chunk" falling out when you try to hang a shelf.

When the plaster starts to fail, the big question is: Do you tear it all out or just cover it up? The short answer is yes, you can drywall over plaster—but it’s not as simple as just screwing boards to the wall.

1. The "Why" Behind the Cover-Up

Demolishing plaster is a dusty, back-breaking nightmare. It involves thousands of pounds of debris and a fine grey powder that will coat everything you own. Drywalling over it (often called "skinning" the walls) allows you to:

• Avoid the mess of a full demo.

• Retain the extra insulation and sound-dampening properties of the original plaster.

• Get perfectly flat, modern walls in a fraction of the time.

2. Evaluate the Stability

You can’t hang drywall on a moving target. If your plaster is bulging or "bouncing" when you press on it, the keys (the plaster that oozes between the wood lath to lock it in place) have broken.

• The Test: Push on the wall. If it gives more than a tiny bit, you need to secure the plaster with plaster washers first or bite the bullet and tear it out.

• Find the Studs: This is the hardest part. Standard stud finders often get confused by wood lath. You’ll need a strong magnet to find the nails in the studs or use a tiny drill bit to "scout" for the solid wood.

3. Choose Your Thickness

Since you are adding a new layer to an existing wall, thickness matters.

• 1/4-inch Drywall: This is the "skinny" option. It’s great because it’s light and doesn't significantly change the depth of your room. However, it’s flimsy and will follow every curve and hump of the old wall.

• 3/8-inch or 1/2-inch: These are sturdier and better for smoothing out wavy walls, but they add significant weight and depth.

4. The Trim Dilemma

This is where most DIYers get stuck. When you add 1/2-inch of drywall to a wall, your electrical boxes will be recessed too deep, and your baseboards, window casings, and door trim will be "swallowed" by the new wall.

• Electrical: You’ll need to install "box extenders" to bring the outlets flush with the new drywall.

• Woodwork: You either have to remove all the trim and reinstall it on top of the drywall (which might require "build-outs" on the door jambs) or use a thinner drywall and accept a shallower look for your trim.

FAQ: Navigating the Plaster-to-Drywall Transition

Q1: Do I need to remove the trim? If you remove the trim it creates a can of worms where the extra 1/4" of drywall will require 1/4" wood pieces over all the window and door extension jambs before putting the trim back. The drywall can be cut up to existing trim and flat taped against the trim for a clean look without all the trim work.

Q2: Should I use screws or adhesive? Use both! Apply beads of construction adhesive (like Liquid Nails) to the back of the drywall and then use long drywall screws (at least 2 or 2.5 inches) to reach through the plaster and lath and deep into the wooden studs.

Q3: Will the extra layer make my room smaller? Technically, yes, by about 1/2" in total width. That's 1/4" drywall on each wall. It's not enough to be noticeable.

Q4: Is it better to just use a "skim coat" of joint compound instead? If the cracks are minor, taping and a skim coat is less work. But if the wall is coming away from the lath or has major cracking, drywall is the permanent solution. Skim coats over loose plaster will just crack again in six months.

Q5: What about the lead paint risk? If your house is old enough to have plaster, it’s old enough to have lead paint. Covering it with drywall is actually an approved "encapsulation" method, which is often safer than scraping or sanding the old paint and sending lead dust into the air.

Are your walls mostly flat with just a few cracks, or is the plaster actually starting to pull away from the lath? Give MrWalls Drywall & Painting a call or text at (413)302-0640 and we will give you options