Fitting a bathroom vanity unit yourself: what it takes

What you need before the cabinet goes anywhere near the wall

Read the installation instructions from the manufacturer first, even if you have hung cabinets before, because basin weight, fixing centres and the depth of the wall bracket vary between models. Check the box contents against the parts list; a missing wall bracket or the wrong length of bolt is the kind of thing you discover halfway up a ladder.

You will need a spirit level, a drill with masonry and tile bits, a stud finder or a simple tapping technique for locating solid wall behind plaster, a pencil, a tape measure, and a set of spanners for the basin waste and mixer. If the basin is separate from the cabinet, dry-fit it on the worktop before you start so you know how it sits.

Turn off the water supply to the bathroom before you touch any existing pipework, even if you think you are only removing an old cabinet. Old flexible hoses perish quietly and a stopcock that has not been touched in years is worth testing before, not during, the job.

Finding the right spot and the fixing points

Mark the height of the cabinet against the existing waste and supply pipes rather than against a number from the instructions, since pipe positions in Estonian bathrooms vary a good deal between a 1930s wooden house in Kalamaja and a panel block from the Soviet era. Standard basin height sits around 80–85 cm to the rim, but check what suits the people using it.

Behind tiles you are usually fixing into either a solid masonry wall, a lightweight partition, or a stud wall clad in waterproof board, and each behaves differently under load. Tap the wall or use a stud finder to establish which one you have before you commit to a drilling pattern, because a cabinet loaded with a full basin needs at least two solid fixing points, ideally more.

If the wall turns out to be a thin partition with no solid backing at cabinet height, that is the point to stop and ask whether the wall itself needs reinforcing before anything is hung on it. This is a case where our odd jobs service, from 39 € an hour, is often used to fit a backing batten or bracket before the cabinet goes up.

Which wall plugs work in a damp room

Ordinary plastic wall plugs made for dry plasterboard are not enough behind a bathroom vanity carrying a basin and water. For solid masonry or concrete, use metal frame anchors or heavy-duty sleeve anchors rated for wet or damp conditions, sized to the drill bit specified on the packaging, not guessed.

Drilling through tile needs its own approach: start the hole with a tile bit at low speed and no hammer action to avoid cracking the glaze, then switch to a masonry bit and hammer action once you are through into the substrate. A strip of masking tape over the drilling point stops the bit skating across the glaze.

For stud walls or waterproof board with no masonry behind them, cavity anchors rated for the expected load are the minimum, but a timber batten screwed into the studs first is the safer route for anything heavier than a small cloakroom basin.

• Metal frame anchors or sleeve anchors for solid masonry, not plastic wall plugs
• Tile bit first at low speed, then masonry bit with hammer action once through the glaze
• Masking tape over the mark to stop the bit wandering on tile
• Cavity anchors or a fixed batten for stud and board walls
• Always match anchor size and load rating to the actual weight of cabinet plus basin plus water

Lifting the cabinet and getting it level

Lifting a vanity unit alone is possible but awkward; a second pair of hands to hold it against the marked height while you check level is worth arranging, especially with an integrated basin where the whole unit is heavier and more rigid than a cabinet alone.

Fit the wall bracket first if the design uses one, checking it is dead level with a spirit level before drilling, since even a few millimetres out shows up as a visibly tilted basin rim once everything is fitted. Hang the cabinet on the bracket, then check level again with the cabinet loaded, not empty.

Tighten fixings gradually and evenly rather than fully on one side first, and give the cabinet a firm push test once mounted, front and to each side, before you connect any plumbing. It should not move or creak.

Connecting the basin, waste and mixer

With the cabinet level and secure, fit the basin waste with its rubber and plastic washers, hand-tight plus a careful quarter turn with a spanner, not forced. Connect the waste pipe to the existing soil pipe using the flexible connector, checking the fall is towards the pipe so water does not sit in the trap incorrectly.

The mixer tap connects to the supply with flexible hoses; hand-tighten the hose nuts onto the tap tails, then finish with a spanner, checking the washers are seated. Turn the water back on slowly and check every joint, including the ones you did not touch, for drips over the next few minutes.

If the existing supply pipes are corroded, the stopcock does not hold, or the pipe positions do not line up with the new basin at all, that is where to stop and bring in a plumber rather than force a connection that will leak later. Our plumbing service, from 45 € an hour, covers exactly this kind of reconnection and any pipework that needs moving.

Sealing the edges and the final check

Run a bead of sanitary silicone along the join between the cabinet or basin and the wall, and around the basin rim where it meets the worktop, using a mastic gun for an even bead and a wet finger or smoothing tool for a clean line. Skipping this step, or using ordinary decorator's caulk instead of sanitary silicone, is the mistake that shows up as water damage inside the cabinet a few months later.

Leave the silicone to cure for the time stated on the tube, usually 24 hours, before running water near it, and avoid touching the bead while it skins over. A neat, continuous seal matters more for keeping water out than it does for looks, though a steady hand gets you both.

Once cured, run the taps, fill the basin and let it drain, and check the underside of the cabinet for any dampness before calling the job finished. If a neat seal is not something you trust yourself to do, our silicone sealing service, from 45 € per job, covers exactly this final step on its own.