How do I level kitchen units on their adjustable legs?

Adjustable legs exist because floors are not flat and worktops must be. The whole method follows from that: the floor is the variable and the worktop line is the constant, so you work from the worst point of the floor upwards and let the legs absorb the difference.

What you'll need

• Spirit level, as long as you can get — 1.2m or more
• Adjustable spanner or pliers, if the legs are stiff (optional)
• Laser level, for a long run (optional)
• Torch

Step by step

1. Empty the units and take the plinth off.The legs are only reachable with the plinth off, and a loaded unit will not shift on its legs without a fight.
2. Find the highest point of the floor along the run.Rest a long level on the floor at several points and find where it reads highest. That is the point that sets the height of everything, because a unit cannot go lower than its legs' minimum.
3. Set the unit at the high point first, and set it low.Wind its legs down to near their minimum, check it is level in both directions, and treat that unit's top edge as the reference line for the whole kitchen.
4. Work outward, matching top edges rather than measuring from the floor.Put the long level across the top of two adjacent units and adjust the second until the bubble reads centre. Repeat along the run. A laser level set to the reference line makes this much faster on a long kitchen.
5. Check across the depth as well as along the run.A unit that is level along the front and tipping backwards puts the worktop out of level in the direction water runs. Check front to back on every unit.
6. Deal with a rocking unit by finding the leg that is not touching.Press each corner in turn. The corner that moves has a leg short of the floor — wind that leg down until it takes weight, then re-check level. It is never the floor's fault; it is one leg out of four.
7. Screw the units to each other once they are level.Two or three short connecting screws through adjoining side panels, near the front and near the top. That locks the levelling in and stops individual units drifting.
8. Fix the run back to the wall.Base units are usually screwed through the back rail into the wall at each end and periodically along the run. It stops the run walking forward as drawers are pulled.
9. Recheck after the worktop goes on.The worktop's weight can settle a unit a fraction. Put a level on the finished worktop, and adjust the legs through the plinth gap if anything has moved before the plinth goes back.
10. Refit the plinth last.It clips onto the front legs and it is cut to whatever height the levelling ended up at, which is why it goes on after the levelling and not before.

Tips

• A short spirit level lies to you on a kitchen. It reads the local high spot rather than the run, and it will happily tell you that every unit is level while the worktop line wanders. Borrow a long one.
• If a leg will not turn, it is usually seized in its socket by a spill that has dried. Penetrating oil and pliers, or replace the leg — they are a couple of pounds each.
• On an appliance space, level the two units either side to each other before installing the appliance. The appliance's own feet then adjust into the gap, rather than the gap having to fit the appliance.

Common mistakes

• Levelling each unit against the floor beneath it — The floor is not a datum. Two units both level on a sloping floor still have their tops at different heights, and the worktop shows it.
• Setting the first unit at the low point of the floor — Every other unit then has to wind down below its minimum to match, which it cannot. Start at the high point and work up.
• Packing a rocking unit with card or shims — The leg is adjustable, which is exactly the problem it was designed to solve. Packing compresses over time and the rock comes back.

Questions people ask