Fitting a bathroom cabinet in a damp room without it coming loose

What kind of cabinet and fixing a damp room actually needs

Chipboard cabinets with a paper laminate are common and cheap, but in a bathroom the laminate lifts at the edges once moisture gets in, usually within a couple of years near a shower. Where you can choose, pick a cabinet with a moisture-resistant or lacquered carcass, or one with an aluminium or PVC frame, rather than plain MDF or chipboard.

The fixings matter as much as the cabinet. Ordinary zinc-plated screws will do for a hallway shelf but rust in a bathroom's humidity, staining the wall around the screw head within a year or two. Use stainless steel screws, or at least A2-rated ones, and stainless or nylon wall plugs rather than the cheapest plastic ones that go brittle with heat and moisture.

Check the fixing points on the back of the cabinet before you buy anything: some mirror cabinets come with a single central hanger, which is not enough weight-bearing for anything holding bottles and jars. Two fixing points spread across the width of the cabinet, ideally into solid material rather than only plasterboard, make for a mount that stays flat against the wall over years of towel-hanging and door-slamming.

How to drill into tile without cracking it

Tile is hard and brittle at the surface and much softer once you are through the glaze, so the first few millimetres are what break it. Mark the hole position with a fine permanent marker, then start the hole with a sharp tile or glass-and-tile drill bit, not a masonry bit, held at a slow speed with the hammer function switched off.

A strip of masking tape over the mark stops the bit skating across the glaze before it bites. Keep light, steady pressure rather than pushing hard, and once you feel the bit break through the glaze into the wall behind, you can usually swap to a masonry bit and switch the hammer action on if the wall is concrete or brick.

Never drill closer than about 15 mm to a tile's edge or a grout line if you can help it, since that is where cracks run. If a cabinet's fixing points do not line up with a safe spot on the tile, it is often better to shift the whole cabinet a centimetre or two sideways than to drill where the tile is most likely to split.

How to seal a screw hole so water cannot get behind the tile

Every hole you drill through a tile is a route for water to reach the adhesive bed and the wall behind, so sealing it is not optional finishing touch but part of the job. Once the wall plug is in and before the screw goes in fully, run a thin bead of sanitary silicone around the rim of the hole so it fills the gap between the plug and the tile edge as the screw is driven home.

Wipe away the excess with a damp cloth or your finger straight away, while the silicone is still workable, so it does not skim over on the surface and leave a hard ring around the screw head. Let it cure for the time stated on the tube, usually 24 hours, before the cabinet takes any real weight or gets splashed.

If you are also fitting the cabinet's edge tight against a wall or another tiled surface, seal that joint too rather than leaving a hairline gap. This is exactly the kind of small, fiddly sealing job that is easy to do badly with a caulking gun and a shaky hand, and it is why we offer silicone sealing as a job on its own, from 45 €, for anyone who would rather have a clean line than a smeared one.

How far the cabinet needs to be from the shower and basin

Manufacturers and electricians talk about splash zones for a reason: the area directly above a basin and within roughly 60 cm of a shower or bath gets wet often enough that anything mounted there needs to be genuinely waterproof, not just moisture-resistant. A laminate cabinet placed right at the edge of a shower screen will take a fine mist every time someone showers, even with the screen closed.

As a rule of thumb, keep a standard bathroom cabinet at least 60 cm from a showerhead or the open side of a bathtub, and mount it high enough above a basin that normal hand-washing does not splash the underside. If your bathroom is small enough that this distance is not possible, that is a sign to choose a fully sealed, waterproof-rated unit rather than to compromise on placement.

Steam is the other factor people forget: a cabinet directly above a radiator or towel rail, or in the direct path of steam rising from a bath, will age faster than one a little further along the same wall, even outside the strict splash zone.

Which tools and materials you will need

Most of what this job needs is standard, but a couple of items are specific to tiled walls and worth having before you start rather than discovering you need them halfway through.

Buying the right drill bit and sanitary silicone in advance saves a trip to the shop with a half-drilled hole and a spirit level balanced on the taps.

• Cordless drill with hammer function that can be switched off
• Tile/glass drill bit and a masonry bit for the wall behind
• Spirit level and pencil or fine permanent marker
• Masking tape
• Stainless steel screws and stainless or nylon wall plugs
• Sanitary silicone sealant and a caulking gun
• Damp cloth for wiping excess silicone

When to stop and call someone instead

If your bathroom walls are tiled over plasterboard rather than solid masonry, finding a proper fixing point can be harder than it looks, and a cabinet that is only screwed into plasterboard behind the tile will eventually pull free under its own weight. If you are not confident locating the stud or noggin behind the board, that is worth having checked before you commit to a hole position.

A cracked tile part-way through drilling, a cabinet with an integrated light or shaver socket, or any work that means moving a socket or light fitting are all points to stop. Anything involving wiring near water is electrical work and should go to a qualified electrician rather than being finished as a DIY job.

For straightforward hanging and sealing, our shelves and mirrors service starts from 39 € per hour, call-out included if the job goes ahead, which for most bathroom cabinets covers the whole fitting in well under the time it takes to do it nervously yourself.