Neodymium magnets can help you find the studs hidden behind drywall.
In many home projects, finding the studs hidden behind drywall can be a challenge. For a simple yet amazingly effective stud-finding solution, get a neodymium magnet. It can’t detect the wood two-by-fours, but it easily locates steel screws that hold the drywall to the studs.
We often use a strong XLTK-BLU magnetic thumbtack for this job. It’s a good size, easy to handle, and we usually have plenty available. (There are always a few stuck to our refrigerator doors.)
If you slowly slide a magnet along the surface of your wall, it will be attracted to the steel drywall screws that come up very close to the surface of the drywall. Even better, you can leave the magnet stuck to the screw to mark the stud throughout your project.
The plastic coated D8APC-BLK is probably our first choice for stud finding, since the smooth plastic finish won’t mark the drywall. We’ve also used a simple D6C cylinder magnet, which is a handy addition to any toolbox.
If you’re not using a Plastic Coated Magnet, cover the magnet with a piece of tape before sliding it all around your painted wall. Neodymium magnets are made of metal which can make marks on the wall. The tape prevents this and helps it slide around smoothly.
You can also use bigger magnets for more strength, of course.
Use magnets to help locate the screws in the studs, but also try to imagine the hidden structure underneath. While magnets are usually helpful, the process is easier if you look for some underlying clues. Many studs are spaced about 16 inches apart. Start your search from one edge of the wall, and work 16” from there. Electrical switches and outlets are often attached to studs, so look for studs on either side of outlets.
Also look for imperfections in the drywall for hints about the locations of the screws. If the wall has settled over the years, these hints may be more obvious. Light the area well while working to highlight minor defects.
Once you find a stud using a magnet, hang a string from the magnet to help make the vertical line of the stud more obvious.
What about if there are no screws? Then you’re out of luck. A magnet can’t “see” a wood stud. If the wall’s construction uses only adhesive to hold the drywall to the studs, a magnet won’t help at all.
What about plaster and lathe construction on older homes? While the rough wood construction might have nails or tacks in it, they’re usually pretty far away from the surface of the plaster. Finding these tiny steel objects with a magnet is difficult at best.
Some studs are made of steel sheet-metal instead of wood two-by-fours. These studs are made of fairly thin steel sheet, bent into a sturdy shape that resembles a two-by-four in size.
Can you detect a steel drywall stud behind ½” or 5/8” thick drywall? Yes, but you need a really powerful magnet. That XLTK-BLU or D8APC-BLK magnet isn’t going to exert enough pull across that distance. You would need a bigger, more powerful magnet like a DCX0 or DEX2 cylinder magnet.
Of course, steel screws are commonly used to anchor drywall to the steel studs. You probably don't need such huge magnets, since finding the screws that are near the surface is still easier. You would only need those bigger magnets if the wall were constructed using only adhesive to hold the wall to the studs, without screws.
The D8APC-BLK plastic coated magnet is our first choice for locating studs. This strong, durable and easily handled magnet is a great addition to any toolbox!