How can I find studs behind my 94-year-old plaster walls??


Three different handymen have told me that their studfinders don't work on my walls. How else can I make sure I'm hanging shelves securely?

  10 answers
  • Dee Dee on Sep 19, 2021

    Prior to the 1950s, most walls were built using a combination of vertical studs, horizontal wooden beams called laths and plaster seams. Because standard stud finders detect a change in density inside the wall, they don't work on lath and plaster – the density inside these walls is not constant enough. If you have just moved into an older home and your stud finder isn't doing its job, invest in a metal scanner instead. Rather than sensing solidity, it locates the nails that fasten the laths to the studs.

    1. Locate an electrical outlet on the wall. Typically, electrical outlets are attached to studs, so they mark a good place to begin scanning.
    2. Calibrate the metal scanner according to the manufacturer's instructions. Slowly move it from left to right across the area above the outlet. Mark the spot on the wall where the scanner lights up,.Continue moving the scanner a few inches farther to the right, then reverse your direction and move it from right to left over the same strip of wall. Mark the first place the scanner lights up in the new direction. It should be close to but not on top of your previous mark. Split the difference between the two marks to find the center of the nail and therefore, most likely, the center of the stud.
    3. Lower the sensitivity on the scanner slightly. Beginning at the nail, move the scanner straight up the wall. If it registers metal at intervals, it is finding a series of nails and you have found a stud. If it registers metal constantly, you have found a pipe inside the wall; in that case, sweep the scanner over a wider expanse of wall to find another spot where it registers metal. Repeat the process there.
    4. Measure 16 inches horizontally from the first stud you find to locate the neighboring stud – most buildings are constructed with a stud every 16 inches. Scan that area to find nails and the exact location of the next stud.

  • William William on Sep 19, 2021

    A strong magnet will work. Find an outlet and remove the cover. Don't touch anything inside. Use a flashlight and see how it's attached. Usually they are screwed or nailed on the side to a stud. Then you can measure 16" from where it's attached to the next stud in the wall.

  • Kathy Gunter Law Kathy Gunter Law on Sep 19, 2021

    You could switch methods and use command hooks or toggle bolts that don’t require studs. You probably have lathe behind it which is mostly wood but not very sturdy in many cases.

  • Mogie Mogie on Sep 19, 2021

    Use plaster anchors made of metal like a molly bolt or a toggle bolt. Be sure to use one that’s long enough to get behind the plaster and lath. When drilling into plaster, you’ll need to use a masonry bit.

  • Vimarhonor Vimarhonor on Sep 19, 2021

    Hello. Here’s a link they could offer some insight I hope this helps.

  • Betsy Betsy on Sep 19, 2021

    Hi Teri: You can try knocking on the wall with your knuckle. When you get to a stud, the sound will be different than when you are on a hollow area. What I have done, in my mom's house which is about 100 years old, is to remove the molding on the floor and try the knocking thing. When I come to an area where I think a stud is, I pound a finishing nail near the floor, about 1/4 inch up, until I find a stud, then, using another nail, finding the other side of that stud. I only pounded them about 1/2 way in. Back in the day they weren't all that careful about the 16" rule, so I went along the floor knocking and looking for studs this way. Some were 16", some 15" some 17" apart. Depended on the day, I guess :) I left the nails in place until I finished what I was doing and then removed them. The molding covered up the nail holes.

    Good luck

  • Simple Nature Decor Simple Nature Decor on Sep 20, 2021

    Stud finder

  • That's tricky and frustrating for sure. The above folks have good tips. Do note that studs are usually 16" on center, meaning from the center of one stud to the next, so if you find one edge, measure 1 1/2" and mark that spot for your stud thickness.