How can you tell if your walls are plaster or sheetrock-drywall?

[jim evans]

I have never lived in a house with plaster walls. A friend asked me how you tell if your walls are plaster or drywall. How do you tell?

[BobK207]

drywall is much softer than plaster....an ice pick (or a push pin) can easily be pushed into drywall.

[RBM]

Go into the attic and look under the insulation

[Edwin Pawlowski]

Take a receptacle cover off and you can usually see. If there is lath, you can probably see the edges.

Age will give you a hint. If the house is 100 years old, chances are it is plaster unless it was re-done. If it is less than 50 years old, 99% chance it is drywall. It was invented in 1916, but did not become popular until after WWII.

[jim evans]

This house was built in the mid 50's

[jim evans]

That seems like a good test, assuming it is very difficult to push a push-pin into a plaster wall.

Thanks

[Blattus Slafaly]

Try to punch a hole in the wall, If you break your hand, it's plaster. If you make a big hole, it's dry wall.

[jim evans]

Thanks, that's a good suggestion. In this case the guy's almost blind. He can do minor repairs but and I'm not sure he could do this.

[AZ Nomad]

Or you've hit a stud.

[Norminn]

Take off a couple of electrical receptacle covers and look at the edge of the opening. If drywall, there are most often, but not always, some sign of what it is ... an edge of a seam showing or a nail pattern along a seam.

I thought for quite some time that our condo must have plaster walls, as I could not find any sign of nail pops or other of the usual defects. I was wrong - just a darn good job in a part of the building which hasn't, apparently, settled at all.

[RickH]

I just knock on em. Drywall sounds like knocking on drywall, knocking on plaster sounds like plaster. But if you are not sure, go to an unconspicuous place in a closet and scratch down through the paint with a nail or pick. If you hit paper then you have drywall, if you hit hard white plaster with no paper then its plaster.

[BobK207]

The reason "it seems like a good test" is because it is a good test.

there's no "assuming" going on here, it's called experience...unless the plaster is in terrible shape, a push pin won't push in.

Depending on where the house is & the quality of construction it could go either way. I've seen lots tract houses from the 50's & 60's, some drywall, some plaster, some skim coat plaster.

Drywall (at least in SoCal) pretty much took over the market by the end of the 60's.

Why the curiosity about wall type?

[JohnR66]

Is there such a thing as plaster board? While renovating the upstairs of my

1942 home, I could see the back side of the walls in the stair case. There was no lath and the stuff crumbles when I try to nail into it to hang a picture. It seems to be a plaster sheet product. It may have had a paper backing, I don't recall.

[N8N]

eh, might not tell you for sure. My house was built in '48 or '49 and it has plaster over gypsum sheet lath - looks like drywall from behind.

nate

[Artful Dodger]

My house was built somewhere in the 40's if not earlier. When I had the bathroom remodeled in 1978 (I think) I saved all that gorgeous lath that they took out of the walls. Have used it for so many little projects! Like building a screen n front of the trash area in back, and building screens for under the back porch. Sigh! They don't make 'em like they used to...

[marlenetrubador]

I always like hitting a stud. I hit one with my car once and we had great sex.

Marlene

[jacy]

That's what my 60-year old midwestern house has. Like drywall but with plaster.

[aemeijers]

Old version of what they now call 'blue board' plastering. Instead of lath, they nail up panels with a rough surface, or even a grid of small holes o give a key, and skim coat that with plaster. Much less labor than nailing up miles of lath a strip at a time, and doing 2-3 coats of plaster.

Very durable when properly installed, but not real DIY friendly for modifications, repairs, or hanging pictures. Would have been quite common in a 1940s house. Sometimes still used in high-end custom houses and restorations- TOH used to show it almost every year.

As to how to tell- I always use the knuckle rap and warm palm tests. Drywall almost always sounds very hollow in the middle of stud bays when you rap on it, plaster usually doesn't. And drywall feels warm under your palm in seconds, since it has a paper surface. Plaster sucks the heat out, and feels cooler longer. Failing that, pull an outlet cover and probe outside the edge of the box with a tiny scewdriver- the paper surface layer will be easy to see.

-- aem sends...