How to Use a Stud Finder to Mount a TV Safely

Why drywall alone will not hold a TV

Standard drywall is roughly half an inch of gypsum board over air. A single plastic drywall anchor is rated for a few kilograms, and a 55 inch television with its mount easily weighs 15 to 25 kilograms concentrated on four small screw points. The wall does not fail on day one. It fails gradually, as the anchors work loose every time someone leans on the console below or the house settles slightly with the seasons, until one day the whole bracket comes away from the wall at once, usually taking a chunk of drywall with it. Framing lumber, by comparison, will hold several hundred kilograms through a single properly driven screw, which is the entire reason this extra step is worth the ten minutes it takes.

Finding the stud, step by step

An electronic stud finder works by sensing a change in density behind the drywall, and it is more reliable used slowly and methodically than swept quickly across the wall.

1. Hold the stud finder flat against the wall at least a foot outside where you expect a stud to be, and switch it on so it can calibrate against open wall.
2. Slide it slowly and level in one direction. It will beep or light up as it crosses each edge of the stud.
3. Mark both edges lightly in pencil. The centre of the stud is the midpoint between them, not the first beep you hear.
4. Confirm with a second pass a few inches higher or lower. Studs run vertically, so a real stud lines up between both passes.
5. Once you have found one stud, measure 16 inches to either side to find the next, since most Tri-Cities homes built after the 1970s frame on 16 inch centres.

Confirming before you drill

A stud finder narrows down a location. It does not guarantee there is nothing else back there, so it is worth a thirty second check before committing to a hole for the lag bolts.

1. Drive a small finish nail at a slight angle into the spot you believe is the stud centre.
2. If it goes in solid and does not wander sideways, you have found wood.
3. If it feels hollow or suddenly pushes in with no resistance, move over half an inch and try again.
4. Fill the test hole later with a dab of paint or filler. It is far cheaper than a hole through drywall in the wrong spot.

Mounting the bracket onto the studs

With the stud locations marked, the mounting itself is mostly about keeping everything level and using hardware rated for the screen weight.

1. Hold the mounting plate against the wall at the height you want, level it, and mark the bolt holes through the plate onto the wall.
2. Pre-drill pilot holes into the marked stud centres so the lag bolts do not split the framing.
3. Fix the plate to the studs with lag bolts rated for the mount, not the drywall screws that sometimes ship in the box for stud-free spots.
4. Attach the arm bracket to the back of the television using the hardware supplied with the mount, matching the VESA pattern on the back of the screen.
5. Lift the television onto the wall plate with a second person supporting the weight, and confirm it locks or latches before letting go.

When the studs do not line up with the bracket

Most TV mounts have a range of horizontal slots, so the bracket rarely needs the studs to be in exactly the right place. On older homes with non-standard framing, on a chimney breast, or over a fireplace where there is often no stud at a useful height at all, that is where rated hollow-wall anchors, sized for the full combined weight of the mount and screen, take over from a wood screw. A heavy-duty toggle anchor into solid drywall can hold a genuine amount of weight when it is the correct one for the load, but fixing into a stud or a piece of blocking added specifically for the job is still the stronger answer whenever the layout allows it.