What is Lath and Plaster?

Lath and plaster is a construction method used for finishing walls. Thin strips of wood—called laths—are nailed horizontally to span the gap between wall studs. Then, plaster is spread over the laths to create a solid wall surface. Lath and plaster is commonly found in homes built before 1950. Newer homes are almost always constructed using drywall instead of lath and plaster. This is because drywall is less expensive, requires less upkeep, and is more fire-resistant.

What is Lath and Plaster Made From?

The laths in lath and plaster are typically made from wood, although metal laths have been produced. Laths are thin strips of wood, only about ¼-inch (6 mm) thick and 1 inch (2.5 cm) wide. They are nailed so that they span the space between bare wall studs. There is typically a ⅜–½-inch gap between each lath. Looking at a lath wall without any plaster is a bit like looking at a fence where the laths are the fence boards and the wall studs are the fence posts.

• Lath and plaster walls are made of plaster spread of metal lath or wooden lath.
• Laths are nailed like fence boards, spanning the distance between wall studs.
• Plaster is made from gypsum mixed with wood pulp and other thickening agents.
• Several coats of plaster are spread over the laths to make a smooth wall.

The plaster used in lath and plaster is made from gypsum mixed with starch, paper pulp, or other thickening agents. This plaster is spread across the laths in several coats. The first layer is a rough plaster that coats the laths, filling the gaps between individual laths. Subsequent coats of plaster are finer and leave the wall with a hard, smooth finish.

How Do You Know if Your Wall is Lath and Plaster?

If you’re not sure what your walls are made of, use our guide to determine if they are made of drywall or lath and plaster. Some of the easiest ways to find out what your walls are made of are:

• Remove a switchplate to get a look at the wall material around the edges of the electrical socket.
• Check an attic area that may have unfinished walls.
• Look for cracks in your wall—plaster forms spiderweb cracks as it ages, drywall does not.
• Try the pushpin test—plaster is too hard to to press a pushpin into by hand, but drywall is softer

You can also use the age of your home as a good way to figure out what your walls are made of. Builders began switching from lath and plaster construction to drywall in the mid-1940s. Most buildings in North America built from 1950 on are made with drywall. Older buildings will most likely have lath and plaster.

Does Anyone Still Use Lath and Plaster?

Very few builders still use lath and plaster during new construction. It’s much more expensive than drywall and it is far more flammable. Drywall is the safer, cheaper option so it is used in almost all modern buildings.

• Lath and plaster is not typically used during construction anymore.
• Building with plaster is more expensive, time consuming, and more flammable than drywall.
• Sometimes, damaged lath and plaster will be replaced or covered with drywall.

Although some builders will maintain old buildings by using lath and plaster, in many cases damaged lath and plaster will be replaced with drywall. This leads to buildings where some sections of the wall are plaster, while others are covered with drywall.

What are the Benefits of Lath and Plaster?

Lath and plaster walls provide much better soundproofing than drywall. This means that interior walls made of lath and plaster will dampen noise very well without adding additional soundproofing. Additionally, lath and plaster walls have a textured design that shows their craftsmanship. Many find this look more appealing than drywall.

• Superior soundproofing.
• Handcrafted look and feel.
• Curved and contoured design features.

One of the biggest benefits of using plaster instead of drywall is that it’s much easier to create curved surfaces. Archways, columns, and rounded design features are much simpler to create with plaster than drywall. This explains the unique architectural features found in many antique homes.

What are the Downsides of Lath and Plaster?

The biggest downsides of traditional lath and plaster are that it is difficult, time-consuming, and expensive to install. Proper plaster techniques for lath require practice and skill. It’s much easier and faster to hang drywall. Furthermore, wood lath and plaster walls are less fire-resistant than drywall. The wooden lath backing the plaster is much more prone to catching fire than drywall.

• Installing lath and plaster is expensive and time-consuming.
• Working with wet plaster requires practice and expertise.
• Wooden lath and plaster has poor fire-resistance.
• Cracks easily form in plaster.
• Many old plaster walls have poor insulation.

Plaster walls crack over time as your home settles. This leads to long, thin spiderweb cracks. These require regular patching to keep your home looking pristine. Finally, lath and plaster walls are not always insulated, and it can be difficult to add insulation to an existing plaster wall.

Lath and Plaster Health Risks

Although most plaster used for your walls or plaster ceiling is made of gypsum, some plasters were historically mixed with asbestos. This makes working with plaster potentially hazardous to your health. Always wear this NIOSH/MSHA-approved mask as well as goggles when working with plaster walls. In order to stay safe in the presence of asbestos, review these OSHA guidelines.

Do Plaster and Lath Walls Have Studs?

Traditional lath and plaster walls do have studs. The laths are nailed to the studs. Like homes built using drywall, the studs in lath and plaster walls are typically 18–24 inches apart (45–60 cm).

• There are studs in traditional lath and plaster walls.
• Stud spacing in lath and plaster is similar to what’s found in new buildings.
• Stud finders designed for drywall may not work on lath and plaster walls.
• Use this stud finder to locate studs in a lath and plaster wall.

It may seem like your plaster walls don’t have studs because lath and plaster can confuse traditional stud finders. Instead of a stud finder designed for drywall walls, use a magnetic stud finder. It will activate when you reach a stud because it will detect the nails used to attach the wood laths to the studs.

When Did They Stop Using Lath and Plaster?

Lath and plaster was gradually phased out of new construction in the United States during World War II. Although drywall was invented decades earlier, it was not popularized until labor shortages during the world war compelled builders to shift towards building methods that required less expertise.

• Drywall began to take the place of lath and plaster during WWII.
• Beginning in the 1950s, the majority of new construction was completed with drywall instead of plaster.
• New homes built today use drywall, not lath and plaster.

By the 1950s, most new construction was completed using drywall instead of lath and plaster. By the 1960s, lath and plaster was almost entirely phased out of new construction. Traditional lath and plaster walls have become increasingly rare as older buildings are demolished or renovated. If you have a traditional lath wall or a plaster ceiling with ornamentation, enjoy the little piece of history.

What is Lath and Plaster Construction?

Lath and plaster construction consists of the following:

• Narrow strips of wood, called laths, nailed horizontally between wall studs.
• A rough layer of plaster spread over the laths to fill gaps between laths.
• A final coat of hard, smooth plaster to create the finished wall surface.

This building method is no longer commonly used, but can still be found in buildings constructed prior to World War II. Although lath and plaster requires more upkeep than drywall, many homeowners retain it for its charm.