Drywall vs. Plaster: What's the Difference and Why It Matters for TV Mounting

If you live in a home built before the 1950s in Los Angeles — and a lot of people do, especially in East Hollywood, Koreatown, Los Feliz, and the older parts of the city — there's a good chance your walls aren't drywall. They're plaster. And that changes everything about how you mount a TV.

What's the Difference?

Drywall (also called sheetrock or gypsum board) is the standard wall material in homes built after the 1950s. It's made of gypsum plaster sandwiched between two sheets of paper, cut into large panels (typically 4'x8'), and screwed to the wall studs. It's soft enough to cut with a utility knife, and finding studs in it is straightforward with a magnetic or electronic stud finder.

Plaster is applied wet in multiple coats over a base of wood slats (called lath) or metal mesh. It hardens into a very dense, solid surface. It was the standard until drywall took over, and it has some genuine advantages — it's more soundproof, fire-resistant, and durable. But it's also much harder to work with when mounting heavy objects.

How to Tell Which You Have

• Age of the home: Pre-1950s? Probably plaster. Post-1960s? Probably drywall.
• Knock on it: Drywall sounds hollow. Plaster sounds solid and dense.
• Try a small pin push: A thumbtack pushes through drywall relatively easily. Plaster resists and often crumbles slightly at the surface.
• Look at cracks: Drywall cracks in straight lines. Plaster cracks in irregular, spider-web patterns.
• Check an outlet box: Remove the cover plate — drywall will have a clean, flat edge. Plaster will show multiple layers and rough texture.

Why It Matters for Mounting

Several key differences affect how you should approach a TV mount on plaster:

Stud finders struggle with plaster. Most magnetic stud finders can't penetrate the dense plaster to detect the nails or screws in the lath. Even electronic models give inconsistent readings. Finding studs in plaster often requires tapping, using a deep-scan stud finder, or using the "knuckle knock" method and verifying with a small test hole.

Plaster cracks easily. Drilling into plaster without proper technique causes the surface to crack and chip. You need to use a sharp, carbide-tipped bit, start slow, and never use the hammer function on your drill for the initial entry.

Lath spacing matters. Behind the plaster, wood laths run horizontally about 1.5" wide with gaps between them. If your drill hits a gap, you need to use a toggle anchor instead of a wood screw. If it hits the lath, the lath alone isn't strong enough for a heavy TV — you still need to find the stud behind it.

Best Approach for Plaster Walls

1. Use a deep-scan stud finder or tap along the wall to locate studs
2. Place masking tape over your drill target — it reduces surface cracking
3. Start with a small pilot hole using a sharp bit at low speed
4. If you find solid wood behind the plaster: great, use a 3" lag bolt
5. If you hit a void: use a heavy-duty toggle anchor rated for 50+ lbs