How do I choose the right wall fixing?

Every failed fixing is a mismatch between the fixing and either the wall or the load. There are only about five types worth knowing, and choosing correctly takes less time than repairing the hole after the wrong one lets go.

What you'll need

• Cable and pipe detector
• Stud detector (optional)

Step by step

1. Determine the wall type by knocking and by pushing a pin into it.Hollow sound and a pin that pushes in: plasterboard. Dull and solid: brick, block or dense plaster on masonry.
2. Estimate the load honestly, including what the shelf will hold in two years.Books are far heavier than most people estimate — a metre of paperbacks is around 20kg.
3. In masonry, use a nylon or plastic plug matched to the screw and drill a masonry bit of the plug's stated diameter.The plug packaging states both the drill size and the screw size. Follow both.
4. In plasterboard, find a stud first if you possibly can and screw directly into it.A screw into a timber stud is stronger than any hollow-wall anchor by a wide margin.
5. Where there's no stud, use a proper hollow-wall anchor rated for the load.Self-drive nylon anchors for light loads; metal expanding anchors or spring toggles for heavier ones.
6. For heavy loads on plasterboard, use spring toggles or a hollow-wall bolt.These spread the load across the back face of the board rather than crushing the front.
7. Check the rating on the packet and halve it for anything cantilevered or repeatedly loaded.Ratings assume a straight downward pull. A shelf end applies leverage that the number doesn't account for.

Tips

• Buy a mixed pack of quality fixings rather than the cheapest — the failure cost is a damaged wall, not just a wasted fixing.
• Drill masonry with hammer action on; drill plasterboard with hammer action off, or you'll blow out a crater.
• If a plug spins in the hole rather than gripping, the hole is oversized — move along and try again, or use a larger plug.
• In old lath-and-plaster walls, treat it as plasterboard but expect variable results; fixing into the timber laths is much more reliable.

Common mistakes

• Plastic plugs in plasterboard — Nothing to expand against. They pull straight out under load.
• Drilling plasterboard on hammer setting — It shatters the board rather than cutting a clean hole.
• Ignoring the load rating — The published figure is the best case for a straight downward pull, not a shelf with a lever arm.

Questions people ask