How do I find a stud in a wall without a detector?

A stud detector is inexpensive and worth owning. But they misread on lath and plaster, over foil-backed board and near cables, so knowing how to work it out by observation is genuinely useful even when you own one.

Safety

Step by step

1. Work out what the wall is first.Knock across it. A hollow drum means plasterboard on studs. A dull dead thud means solid masonry, and none of this applies — you want a masonry fixing instead.
2. Tap along the wall listening for the change.Knuckle or the handle of a screwdriver, moving horizontally in small steps at about chest height. The sound goes from hollow to noticeably solid over a stud. Mark both edges of the solid section.
3. Use the standard spacings.Studs are usually at 400mm or 600mm centres. Once you have one, measure along and check at those intervals. Two confirmed studs give you the spacing for the whole wall.
4. Look at the skirting board.Skirting is nailed into the studs. Nail heads, filled dimples, or a line of slightly proud paint along the skirting mark stud positions exactly, and they run straight up the wall.
5. Check around sockets and switches.A back box in a stud wall is usually fixed to the side of a stud. That tells you a stud is immediately beside it — and also warns you that a cable runs vertically from it, which you must avoid.
6. Look at the ceiling and corners.There is almost always a stud in each corner and at each side of a door or window opening. Starting from a corner and measuring out is often quicker than tapping.
7. Use light across the wall.A torch held flat against the wall shining along it shows very slight dimpling where the board is screwed to the studs. It works surprisingly well on a painted wall in a dark room.
8. Confirm with a fine pin.A panel pin or a fine bradawl pushed through the plasterboard somewhere that will be hidden — behind where the fitting goes, or low behind furniture. Resistance after about 12mm means timber.
9. Find both edges to get the centre.A stud is typically 38-50mm wide. Probe to find each edge and fix into the middle. A screw into the very edge splits the timber and grips poorly.
10. Use a magnet as a last resort.A strong magnet dragged slowly over the wall finds the screws or nails holding the board to the studs. Slow, and reliable once it catches.
11. Use a plasterboard fixing if there is no stud where you need one.Do not move the shelf to suit the stud if the load is light. Modern plasterboard fixings hold a great deal when sized correctly.

Tips

• Mark stud positions in pencil along the wall before you start. Finding them once and using them repeatedly is far quicker than searching per fixing.
• Ceiling joists work the same way and are usually at 400mm centres too. The same tapping and probing applies.
• In an older house, lath and plaster behaves differently — the laths give a fairly even sound and detectors are unreliable. Probing is the practical method there.

Common mistakes

• Drilling directly above or below a socket — Cables run vertically from back boxes. This is the single most common way people drill into live wiring.
• Fixing into the edge of a stud — The screw splits the timber and holds badly. Find both edges and go into the centre.

If it doesn't work

Questions people ask