How to measure a bathroom alcove for a bespoke vanity

For a vanity between two walls, one width measurement is only a starting point. Record the opening where the cabinet and worktop will actually sit, note any unfinished surfaces, and have your installer agree the final fit before approving production dimensions.

Start with a sketch and labelled measurements

Draw a simple front view and plan view of the alcove. Mark left and right as you face the vanity, and write every measurement in millimetres. Add the date and whether the walls and floor are finished.

Use a tape measure or a laser measure according to its instructions. Check the reference point before recording a laser reading: Bosch's PLR 50 C instructions distinguish readings from the rear edge, front edge and extended stop plate. The point you place against the wall must match the selected setting.

Keep the original readings on the sketch. If two measurements disagree, repeat them from the same marked positions rather than choosing the number you expected.

1. Measure across the opening at more than one position

Mark the proposed worktop level and the zone the cabinet will occupy. Measure across the alcove near the back wall and again near the intended front edge. Repeat at relevant cabinet heights so your installer can see whether the opening changes through the space the unit needs.

Include any projecting tile trim, skirting or boxing that will remain. If something will be removed, label that separately; do not silently leave it out of the drawing.

Here is an illustrative set of readings at one proposed worktop level:

These readings vary by 8 mm. Send all three, with their positions, rather than averaging them into one width. The narrowest recorded point flags a constraint; it is not automatically the width to manufacture.

2. Record depth and the space in front

Measure from the finished back-wall position to the intended front edge on both sides. Show nearby door frames, a shower screen, a radiator and any other feature that limits the projection.

Then sketch the bathroom door swing and the space needed to open the proposed drawers or doors. Ask the installer to review both the closed unit and its moving parts. A countertop outline alone does not show whether the storage will be easy to use.

This wider room record is consistent with IKEA's bathroom measuring checklist, which includes doors, windows, water pipes, ventilation and neighbouring fixtures. Use it as a reminder to capture obstacles around the alcove as well as the walls themselves.

3. Separate finished surfaces from planned finishes

Say whether each reading is between finished tiles, bare plaster or another surface. If tiling, wall lining or floor work is still planned, ask the relevant trades to confirm the intended finished positions.

Keep the measured opening and the proposed finished opening as separate labelled values. Do not subtract an assumed tile thickness on behalf of the installer. Adhesive, backing and changes to the wall may also need to be considered.

Have the installer check whether the walls are straight, plumb and square through the proposed fitting area. A list of widths helps reveal variation, but it does not fully describe a bowed wall or establish that a rectangular unit can be installed.

4. Locate plumbing from a clear reference

On the same drawing, record the visible waste and water connections from a named side wall and the finished-floor level, or clearly label the current floor if it will change. Add photographs with the measuring positions visible.

Ask your plumber to confirm which connections will stay, which will move and how the waste and supplies relate to the basin and drawers. For an integrated basin and worktop, coordinate those positions with the chosen tap before the layout is signed off.

Keep pipe positions distinct from the basin position you want. They are information for the layout review, not an instruction to place the bowl directly over every existing connection.

5. Agree the fitting allowance and installation route

The room opening, cabinet width and worktop width may be different dimensions. Ask the maker and installer to identify each on the final drawing, along with any proposed side gap, filler or wall-junction detail.

There is no single deduction to apply to every alcove. The agreed allowance needs to suit the actual walls, finishes, materials and installation method. Confirm whether any trimming or scribing is permitted for the specified component before planning around it.

Also show how the pieces will reach the room and move into position. A unit that appears to fit on a plan still needs an agreed installation sequence. Confirm who checks the final site dimensions before production.