When This Approach Makes Sense
Going over existing plaster works well when the plaster is bonded to the lath, not pulling away in chunks, and not hiding active moisture. If you push on the wall and feel give, or you see brown staining, stop and figure out what's going on first. Drywall over loose plaster just creates a bigger problem to fix later.
It also makes sense when you don't want to deal with demolition. Removing plaster and lath in a single hallway can mean two days of dust, a dumpster rental, and a lot of nail removal. My brother-in-law had a kid napping down the hall, so the demolition route was a no-go. Quarter-inch drywall over the plaster added about a quarter inch of thickness to each wall, which we adjusted for at the door casings without much trouble.
Materials and Tools You'll Need
Here's what we bought for a roughly 200 square foot hallway. Costs are from a Home Depot run in March 2026, so adjust for your area:
- Quarter-inch drywall sheets (4x8): $14 each, we used six
- 3-inch coarse drywall screws: $9 per box of 100
- Joint compound (premixed, 4.5 gallon): $18
- Mesh joint tape: $7 per roll
- Stud finder (we used a Franklin ProSensor): $50
- Drywall T-square: $22
- Utility knife with sharp blades: $8
Total materials came in around $230. The stud finder was the most important tool. A cheap one will lie to you when there's plaster and lath in the way. The Franklin model uses multiple sensors and was the only one that gave us reliable results. If you don't want to spend $50 on a stud finder, you can hammer-test or use a strong magnet on screws or nails in the lath, but expect that to take a lot longer.
Step 1: Find and Mark Every Stud
This took us about an hour for the hallway, and it was time well spent. We found one stud, then measured 16 inches in each direction to predict the next, then verified with the stud finder. Some 1960s homes have inconsistent stud spacing, especially around windows and doors. My brother-in-law's hallway had a 14-inch gap in one section where someone had added a wall section years ago.
Mark each stud with a vertical pencil line floor to ceiling. We also marked the floor and ceiling with painter's tape so the marks would still be visible after we hung a sheet against the wall. Losing your stud marks halfway through hanging is a frustration you do not want.
Step 2: Score and Snap Your Sheets
Quarter-inch drywall scores and snaps just like half-inch, but it's more flexible and easier to break wrong. Score the front paper with a sharp utility knife guided by your T-square, snap it back over your knee or a counter edge, then run the knife down the back paper to finish the cut. New blades make a huge difference. We changed blades after every other sheet.
Measure your sheets to land on stud centers. If your studs are at 16 inches on center and your sheet is 48 inches wide, you'll hit a stud at 16, 32, and 48. The 48-inch edge needs to land on a stud so the next sheet's edge can also be screwed into it. Plan your layout before you start cutting.
Step 3: Hang the Sheets
Three-inch coarse-thread drywall screws are long enough to go through the quarter-inch drywall, the existing plaster (typically three quarters of an inch thick), and bite at least an inch into the wood stud. We tested a few screws first to confirm they were grabbing solidly. If your plaster is thicker than three quarters of an inch, step up to three-and-a-quarter or three-and-a-half inch screws.
Set screws every 12 inches along studs, and dimple them just below the surface of the new drywall paper without breaking through. A drywall screw setter bit is worth the $4 it costs because it stops the screw at the right depth automatically. Without one, you'll spin a few too deep and have to back them out and reset them.
The horizontal seam between two sheets stacked vertically is the trickiest part. The plaster behind isn't flat. Sometimes the upper sheet wants to bow out slightly. Push it firmly against the plaster while screwing along the studs, and add a couple extra screws near the seam to keep both sheets tight.
Step 4: Tape and Mud the Seams
Mesh tape worked fine for us because the drywall sheets were tight against each other. If you had gaps, paper tape with hot mud would be safer. We did three coats of premixed joint compound, sanding lightly between the second and third coat with 150 grit, then a final sanding with 220 grit on a sanding sponge.
The corners where the new drywall meets existing trim or ceiling need careful attention. We caulked those gaps with paintable acrylic latex caulk after the mud was fully dry. Caulk fills small gaps that mud would crack out of.
What I'd Do Differently
Two things stand out in hindsight. First, I'd buy the screw setter bit on day one instead of day two. We over-drove maybe 30 screws on the first sheet before I gave up and went to the hardware store for the right tool. Second, I'd plan the door casing extensions before starting. Adding quarter-inch jamb extensions around three doorways slowed us down on the second day because we hadn't pre-cut the trim pieces.
For specific guidance on plaster condition assessment and when this method might fail, the National Park Service Preservation Briefs Number 21 covers historic plaster repair philosophy and is worth reading: nps.gov plaster preservation brief. The Family Handyman site also has a solid overview of plaster wall repair fundamentals if you're deciding between this approach and a full repair.