What Are Lath and Plaster Walls — and Does My House Have Them?

By Michael Franco

August 15, 2026

If your home was built before the 1950s, there's a good chance your walls aren't drywall. They may be something older, heavier and a lot more interesting to deal with.

This May Also Interest You: What’s a Home Improvement Loan and How Do You Get One?

Lath and plaster construction was the standard for interior walls for decades before drywall took over. A surprising number of older homes still have it — sometimes without the owners realizing it.

What Is Lath and Plaster?

Lath and plaster is exactly what it sounds like — two materials working together to form a wall. The lath is a backing layer of thin wood strips, nailed horizontally across the wall studs or ceiling joists with small gaps between each strip. Over that lath, plaster was applied in multiple layers, typically a rough base coat called the brown coat, sometimes a second leveling coat, and a smooth finish coat on top.

The way it works structurally is genuinely clever. As wet plaster was pressed against the lath, some of it squeezed through the gaps between the wood strips and formed small blobs on the back side once it dried — called plaster keys. These keys are what physically anchor the plaster to the lath, locking the whole assembly together. Older plaster mixes often included a horsehair binder mixed into the brown coat, which added tensile strength and helped prevent cracking as the plaster cured. In some homes, particularly those built slightly later, you'll find wire mesh lath instead of wood strips — a transitional material used before drywall fully took over.

How to Tell If You Have Plaster and Lath Walls

A few telltale signs point to lath and plaster, and most of them don't require any demolition to check.

Tap on the wall. Drywall has a hollow, somewhat papery sound. Plaster sounds noticeably denser and more solid — almost like tapping on stone, because in a sense, you are.

Check the thickness around outlets, switches, and door frames. Plaster walls are typically thicker than drywall — often an inch or more total — which means electrical outlets and switches sit deeper in the wall, and door and window trim tends to be proportionally thicker as well.

Look for cracks. Plaster walls develop a very particular type of cracking over the decades — fine, spiderweb-like cracks that follow the pattern of the lath strips underneath, often appearing in straight horizontal or diagonal lines corresponding to where the wood strips run. Drywall cracks tend to look different — typically along seams and corners rather than in these web-like patterns.

If you have access to an unfinished area — an attic, a closet with an access panel, or anywhere the wall isn't fully finished — take a look at the back side of the wall if you can. Wood lath strips with visible gaps are a dead giveaway.

Finally, consider your home's age. If your house was built before roughly 1950, lath and plaster is likely, though many homes built into the 1960s used it as well, particularly in areas where it remained the regional standard longer.

More Related Articles:

What This Means for You

Living with lath and plaster comes with a few special considerations:

Hanging Pictures on Lath and Plaster Walls

Hanging things is different. The dense, sometimes brittle nature of plaster means standard drywall anchors don't always perform the same way, and drilling into plaster can occasionally cause cracking to spread if you're not careful. Pre-drilling pilot holes and using anchors rated for masonry or plaster generally works better than drywall-specific hardware.

Repairs for Lath and Plaster Walls

Repairs require different techniques. Cracks and small holes in plaster aren't patched the same way as drywall — proper repair often involves a skimming coat of new plaster or a specialized patching compound designed to bond with the old material, and matching the texture of decades-old plaster can take some skill.

Renovations Can Be Tricky

Renovations may uncover surprises. Homes old enough to have lath and plaster were often also built with knob and tube wiring, which has its own safety considerations and is frequently flagged during inspections or insurance evaluations. If you're planning any significant renovation work, it's worth having both the plaster and the wiring assessed together.

Lath and Plaster Vs. Drywall

And finally — many people genuinely love their plaster walls. The thickness provides better sound insulation than drywall, and there's a certain old house charm to the slightly uneven, hand-finished texture that plaster has and drywall simply doesn't replicate. Whether to preserve it, repair it, or eventually replace sections with drywall or modern backing board is often as much a matter of taste and budget as necessity.

Follow us