How does a kitchen wall unit actually hang on the wall?

Almost nobody who owns a kitchen has seen inside the top corner of a wall unit, which is a shame, because it explains every wall unit problem there is. Once you know that the unit hangs from a rail rather than being screwed to the wall, and that the adjustment is inside the cupboard rather than outside, both levelling a run and diagnosing a failure become straightforward.

Safety

Step by step

1. Look inside the top rear corners of the unit.Empty the top shelf and look up and back. You will see a plastic and steel bracket screwed to each side panel, with a hooked steel tongue reaching back through the unit's back panel.
2. Find the rail behind it.That tongue hooks over a steel rail screwed horizontally to the wall. One rail usually runs the whole length of a wall unit run, which is what keeps the units in line with each other.
3. Identify the two adjusting screws.The upper screw bears on the rail and lifts or lowers the unit. The lower screw draws the unit back against the wall. Turning them is how a run of wall units is levelled and pulled flat after hanging.
4. Trace the load path.Contents to shelf, shelf to side panel, side panel to bracket screws, bracket to rail, rail to wall. The weakest link is normally the bracket screws in 18mm chipboard, which is why a dropped unit is usually a chipboard failure rather than a wall failure.
5. Establish what the rail is fixed into.In masonry: long screws with proper frame fixings or nylon plugs into brick or block, not into mortar joints. In a stud wall: screws landing in the timber studs. There is no plasterboard anchor that is an acceptable sole support for a loaded wall unit.
6. Understand why units are also screwed to each other.Adjacent units are joined through their side panels, so the run behaves as one long structure and no single unit can drop on its own. That is why a whole run rarely fails at once and a single unit sometimes does.
7. Recognise the failure sequence.A unit that is starting to go gapes at the top first — because the lower bracket screw is pulling out and the unit is rotating away from the wall. Then it slips down at one end. Both are warnings, not aesthetics.
8. Note what a wall unit is designed to carry.Crockery and food, not a stone mortar collection and twenty tins. If you want to store real weight, put it in a base unit where the load goes to the floor rather than into a wall.

Tips

• If you are hanging units, a batten temporarily screwed to the wall at the right height to rest them on turns a two-person job into a one-person job.
• The rail height matters more than the individual unit heights, because everything hangs off it. Get the rail level and the units follow.
• Dot-and-dab plasterboard on masonry is the awkward case: the screw passes through a void behind the board before reaching the brick, so the fixing must be long enough to get proper purchase in the masonry and the board must not be crushed.

Questions people ask