To determine if the walls in your home are drywall or plaster, first remove a switch plate or electrical socket cover. Inspect the cross-section of the wall to see whether it’s drywall or plaster. Alternatively, go into your attic space to see the backside of the walls. You should be able to see plaster and lath or bare drywall. If your walls and ceilings have hairline cracks in jagged patterns, this is a sign of plaster, not drywall. Keep in mind that drywall was not commonly used prior to WWII, so if you have an older home, it’s likely the walls are plaster.
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What is the Difference Between Drywall and Plaster?
Drywall is a fabricated board made of gypsum sandwiched between two sheets of paper. Drywall is manufactured to uniform thickness. Common thickness for drywall varies between 1/4″ and 3/4″, with 3/8″ and 1/2″ being the most common in homes.
- Drywall is characterized by paper on the front and back, with white gypsum between the sheets of paper.
- Drywall is produced at standardized sizes, such as 3/8″, 1/2″, and 3/4″.
- Plaster walls are made by nailing thin strips of wood (laths) over wall studs. Then, layers of plaster iare spread over these laths to create a smooth surface.
- Plaster is harder and less uniform in thickness than drywall.
Plastering walls is a technique used prior to the invention and popularization of drywall. A series of thin boards, called laths, are nailed over the studs, typically with a small space between each lath. Plaster is then spread over the laths, sometimes almost an inch thick. Some plaster oozes between the gaps in the laths, which leads to the unique look of board and plaster when you see the inside of a plasterboard wall.
5 Ways to Tell if Your Walls are Drywall or Plaster
Drywall and plaster require different techniques when hanging pictures, planning for a remodel, or repairing your walls. So, it’s essential to know what material your walls are made from. Use these simple methods to determine if you’ve got plaster or drywall surfaces in your home.
Remove a Switch Plate
Use a screwdriver to remove a switch plate or electrical socket cover. Once the plastic cover is removed, you should be able to see a cross-section of your wall material in the hole cut for the switch/socket. If there is a layer of paper on either side of crumbly white gypsum, it’s drywall.
- Remove a switch plate in your home.
- Inspect the sides of the hole cut for the switch. Use a flashlight for more light if necessary.
- Drywall is characterized by paper on either side of chalky gypsum.
- Plaster will have layers of solid plaster without paper. You may see thin wood strips beneath the plaster.
If your walls are made of plaster, there will not be a layer of paper on either side of your wall material. There will be rock-hard plaster over wood laths. With the aid of a flashlight, you may even be able to see plaster “keys” where the first coat of plaster oozed between the laths.
Check Your Attic
Most attics are unfinished, meaning that you can see the bare studs and the wall material used on any interior walls and ceilings. Enter your attic and look for any walls with visible studs. If you see uniform, rectangle sheets with brown paper backing, you have drywall. If you see thin strips of wood with hardened white material in the gaps between the wood strips, it’s a plaster wall.
- Check your attic to see the backside of any interior walls or ceilings.
- Drywall will be evident by its brown paper backing.
- Plaster can be identified by wooden laths with plaster visible between them.
- Examine interior walls and ceilings. Exterior walls will not have plaster or drywall.
Remember to check the floor of the attic as well as the walls. The attic floor is really the ceiling of the room below. Additionally, exterior walls will not help you in identifying your wall material. Exterior walls are not finished with drywall or plaster and are usually insulated. The building material on exterior walls will not be visible.
Perform a Hardness Test
One simple test to determine if you have plaster or drywall is to attempt to press a simple push pin into your wall. Drywall is relatively soft, and a push pin can usually be pressed into the wall with thumb pressure. Plaster is much harder than drywall. In most cases, you won’t be able to get a thumbtack in without hammering.
- A pushpin will easily penetrate drywall when inserted by hand.
- Plaster is much harder than drywall. It’s usually impossible to insert a push pin into plaster by hand.
- A small nail can easily be hammered into drywall to hang a picture.
- Plaster resists nails and may “bounce” nails out as you try to hammer them in.
Alternatively, try hammering a small nail into your wall. Drywall will accept a nail easily and produce a small amount of fine white dust. Plaster walls often resist nails. It may even feel like the wall wants to “bounce” the nail out once it gets started. This is due to the flexing of the laths in the wall. When you do get a nail into plaster, the resulting hole is often a bit larger than the nail, resulting in a loose nail that is prone to falling out.
Look for Cracks
Plaster often forms hairline cracks as it ages, while drywall does not. In plaster, cracks take the form of spiderweb-like lines that spread across walls and ceilings. In drywall, any cracking that takes place is usually in small, localized areas where joint compound was used to seal seams or patch holes in drywall. The paper surface of drywall won’t crack.
- Spreading spiderweb cracks are a sure sign of plaster walls and/or ceilings.
- Small cracks or flaking in areas is typically a sign of joint compound on drywall.
- Often, drywall will have no cracks at all.
Because plaster was gradually phased out of building projects in the years following WWII, most plaster walls are old. Age has caused hairline cracks in most plaster surface material, making plaster easy to identify.
Determine the Age of Your Home
Although drywall was invented prior to WWII, it didn’t begin to see regular use in residential construction until after the second world war. Even then, drywall construction didn’t become the standard for homebuilding until after 1960. With this knowledge, as well knowledge of when your home was built, you can determine whether your walls are plaster or drywall.
- If your home was built before WWII, there is an extremely high chance the walls are plaster.
- Homes built between 1945 and 1960 may be plaster or drywall.
- If your home was built after 1960, odds are the walls are drywall.
- Previous homeowners may have renovated and replaced portions of plaster walls with drywall.
Keep in mind that any recent renovations should be considered when determining if your walls are drywall or plaster. The prior homeowners may have renovated an older home, replacing some or all of the original plaster with drywall. In some cases, certain rooms or walls may be drywall, while other portions of your home might retain original plaster walls.
Should You Replace Lath and Plaster with Drywall?
If your walls are functional and you like how they look, there’s no need to tear out the plaster and lath to replace it with drywall. With routine maintenance and painting, plaster walls can be easily kept in good condition. However, if you are undertaking a renovation project that requires you to modify, add, or remove a wall, it’s much easier to complete the new construction with drywall rather than plaster.
- There is no need to replace a plaster wall that is in good condition.
- If you are renovating plaster walls, it’s easier and cheaper to use drywall in the renovation than build new plaster walls.
- Drywall is easy for beginners to cut and install while plastering walls is a multi-step process.
Drywall is favored over plaster because of its fire resistance, ease of installation, and lower material costs. You will get a cleaner end result much faster by installing drywall than you will trying to build new plaster walls. Installing plaster walls requires nailing laths and furring strips, as well as spreading several coats of plaster. In new construction or renovation, drywall is best.
How Do You Tell if Your Walls are Plaster or Drywall?
If you are trying to find out if your walls are constructed from plaster or drywall, try these simple methods:
- Remove a switch plate to see the cross-section of your wall. Paper-backed gypsum indicates drywall. Plaster and lath means you have plaster walls.
- Enter your attic to inspect the backside of the interior walls and ceilings.
- Try to push a push pin into your wall. Drywall is soft enough to accept a push pin, while plaster is too hard to insert a push pin by hand.
- Inspect any cracks in the wall. Cracks in plaster are long and jagged, often spreading across walls and ceilings. Cracks in drywall joint compound are often small and localized.
- Find out when your home is built. Homes built before 1945 are typically plaster, while homes constructed after 1945 have a much higher chance of being built with drywall.
By using one or more of these tactics, you will be able to determine what type of wall you have in your home. From there, you can use the appropriate tools and methods for repairing, renovating, or hanging items on your walls.