How to Put Up a Shelf That Will Not Fall Down

Shelves fall down for one reason: the wrong fixing in the wrong wall. The screws supplied with flat-pack shelving are chosen for cost, not for your house.

Start by identifying the wall.

Identify your wall in ten seconds

Knock on it. A solid, dull thud means masonry — brick, block or concrete. A hollow drum sound means plasterboard on studs.

Push a drawing pin in. If it goes in with thumb pressure, plasterboard. If it stops dead, masonry.

Drill a test hole in an inconspicuous spot and look at the dust. Red or pink dust is brick. Grey is concrete or block. White or grey powder that stops after 12mm is plasterboard.

Fixings for masonry

Drill with the hammer setting and a masonry bit. Match the bit size to the plug, not to the screw.

• Brown or red plastic plugs with 5mm or 6mm screws: fine for light loads. Books, no.
• Frame fixings or hammer-in fixings: long, one-piece, and considerably stronger. Good for a shelf carrying weight.
• Resin anchors: for genuinely heavy loads or crumbly old brick. You inject resin, insert a threaded rod, and wait. Extremely strong.

Drill deeper than the plug is long, so dust has somewhere to go. Blow the hole out or vacuum it before inserting the plug — a hole packed with dust holds a plug at a fraction of its rated strength.

Fixings for plasterboard

Plasterboard has almost no strength of its own. Everything depends on either finding a stud or spreading the load.

1. Find the studs. They are usually at 400mm or 600mm centres. A magnet on a string finds the screws holding the board on. Screw directly into a stud and you can hang almost anything.
2. If you cannot hit a stud, use a proper cavity fixing. Spring toggles and metal collapsible anchors are far stronger than the plastic expanding type.
3. Never use plastic wall plugs in plasterboard. They are designed to expand against solid material. In board they spin, crush the plaster, and pull out.

Putting it up level

1. Hold the shelf or bracket in place and mark one hole.
2. Drill and fix that one only.
3. Swing the bracket to level, checking with a spirit level along the top edge, then mark the remaining holes.
4. Drill and fix the rest.

This is better than marking everything at once, because it lets you correct for a hole that drifts.

Load, honestly

A single 6mm plug in sound brick will hold far more than the shelf will. A single spring toggle in plasterboard is rated for a few kilograms, and that rating assumes a straight downward pull.

Shelves do not pull straight down. They lever, which multiplies the force on the top fixings enormously. A deep shelf loaded at the front can put several times the shelf's weight onto the top screws.

The practical rule: for anything deeper than 250mm or heavier than a few kilograms, get into a stud or into masonry. Cavity fixings are for pictures and light shelving, not for books.