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What are Interior Walls Made Of? [5 Common Materials]

The most common interior wall material in the United States is drywall over wood studs. However, many older homes still feature lath and plaster over wood studs. Alternatively, you may have solid wood boards or wood paneling, depending on the age and style of your home. Even if your home has drywall as the primary wall material, you’re likely to find waterproof wall panels in your shower. This choice is typically made because drywall is not very water-resistant and will be damaged quickly if it is used for the walls and ceilings inside your shower.

What are interior walls made of?

What is Inside Your Walls?

In addition to the finishing material you see every day, there are several elements inside your walls. There are the studs that support the walls. These are typically made of 2x4s or 2x6s. Running within interior walls, behind the wall material is also plumbing, electrical wires, and cooling/heating ducts.

  • Wooden studs
  • Electrical wiring
  • Plumbing
  • Heating and cooling ducts

Before you renovate or remove interior walls, it’s best to determine what’s inside your wall. Use this specialized stud finder/wall scanner to locate wires, plumbing, and other in-wall elements before you begin demolition.

How Do You Know What Material Your Walls are Made Of?

If you’re not sure what your walls are made of, review our guide on how to tell if your walls are made of drywall or plaster. One of the keys to determining the wall material in your home is to remove a switchplate and look at the wall material that was cut to make a hole for the switch. By looking at the edges and cross-section of the hole, you can get a good idea of what your wall is made from.

  • Remove a switch plate to look at the edges and cross-section of wall material around the switch itself.
  • Knock on the walls—hollow walls are made of drywall or thin paneling, while solid walls are plaster or wood.
  • Enter your attic to get a look at the back side of unfinished walls.

Other ways to find out what your walls are made from are to knock the walls—hollow sounds indicate drywall or thin wood-based paneling. Solid sounds typically mean your walls are plaster or solid wood boards. Enter your attic to see if you can find some unfinished walls. Getting a look at walls from the back side can reveal what they’re made of. If you have an older home, take the time to review the types of walls in old houses.

5 Common Materials for Interior Walls

Although exterior walls are generally made of wood, brick, or stone, interior walls are a bit different. Because interior walls don’t need to resist weather to the same degree that exterior walls do, the building materials used are usually simpler. Here are the most frequently encountered wall materials you’re likely to find in your home.

Drywall

Drywall is by far the most common material used to finish interior walls. Drywall panels are manufactured by sandwiching a layer of gypsum plaster between two sheets of heavy manila paper. It’s inexpensive, easy to install, and fire-resistant. The signs that your walls are made of drywall are:

  • Your home was built after 1950.
  • When you attempt to push a push pin into your wall by hand, it goes in relatively easily.
  • Your walls produce a hollow sound when you knock on them.

Drywall wall panels are attached directly to the wall studs with drywall screws. Because they are so easy to install, drywall panels became extremely popular starting in the 1950s. Very few homes built today use anything but drywall.

Lath and Plaster

Homes built in the United States pre-1950 most likely have lath and plaster walls. This wall finishing system consists of strips of wood nailed to the wall studs to form a “fence” between the studs. Then, gypsum plaster is spread over the laths to form a smooth wall surface. You can identify drywall or plaster walls through the following traits:

  • Your home was built prior to 1950.
  • The wall sounds solid when you knock on it.
  • It is very hard—or impossible—to drive a pushpin into the wall by hand.
  • Long, thin cracks are present in the surface of the wall.

Plaster walls greatly decreased in popularity beginning in the 1950s. Plaster walls take more time to install than drywall and are far less fire-resistant. However, plaster allows for curved and contoured design features that are seldom found in homes with drywall. This gives plaster walls a unique charm.

Wood Boards

Solid wood boards are still used to cover interior walls today. They are also present in older homes. The most common types of wood wall materials are:

  • Tongue and Groove Boards: These boards run vertically and are often found in cabins.
  • Wainscoting: A waist-high wood panel that is found in colonial homes or newer construction with a classic twist.
  • Shiplap: Boards that run horizontally along the wall can be found in antique homes or newer remodels.

Solid wood boards will not sound hollow when you knock on them. Also, they hold up well when nails or screws are driven into them to hang decor. Just make sure to double-check your walls. Some newer types of wainscoting are manufactured as thin wood panels, like plywood. They may not be as thick or durable as traditional solid-wood wainscoting.

Wood Paneling

Wood veneer panels were relatively popular during home construction from the 1950s to the 1980s. These panels resemble tongue-and-groove boards but are actually thin sheets of compressed wood fibers with veneer glued on top. In order to tell wood veneer paneling from true boards, look for the following:

  • Inspect the grooves between the “boards.” if it is actually part of one continuous sheet, it’s paneling.
  • The wall will sound hollow when you knock on it.
  • The material is very thin. Nails and screws will pull out of it easily.

Similar to veneer paneling, there are other types of thin wood paneling that may be present in your home. Beaver Board and Masonite are made from compressed wood fibers bound together with resin. These thin boards have a telltale hollow sound when knocked.

Waterproof Paneling

Although drywall is the top choice for home construction today, drywall is not suitable for every area of your home. Shower walls and ceilings are exposed to direct water, which can destroy drywall. Instead, concrete boards or waterproof panels made from extruded polystyrene foam are used in showers.

  • Well-made shower walls and ceilings are made of waterproof panels.
  • Waterproof panels may be made of concrete, polystyrene foam, or laminated wood fibers.
  • Make sure to use waterproof wallboard when you are remodeling your shower.

If you are remodeling a bathroom and find a strange wall material in your shower walls, don’t be alarmed—this is actually a sign of good home construction. Do not replace this material with drywall, even if the drywall is billed as water-resistant. You should not tile over drywall in your shower. A much hardier building material is required.

What Materials Can Interior Walls be Made Of?

The most common materials you will find in interior wall construction are:

  • Drywall
  • Lath and plaster
  • Solid wood boards
  • Thin wood paneling
  • Waterproof paneling

The flat surface of your wall may be hiding a few surprises. In addition to the studs, wires, pipes, and ducts behind the wall, your wall may be finished with a material you haven’t encountered before. By knowing what signs to look for you can quickly identify your wall material.

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