Bathroom cabinet installation, built for steam and service access

Confirm product rating and construction for humid rooms

Not every stylish cabinet is a bathroom cabinet. Look for sealed edges, moisture-resistant carcass materials, finished interiors and hardware that will not rust into orange streaks. Freestanding furniture can work if legs lift it out of splash and the finish is honest about water. Ask what happens to the carcass if a supply weeps for a weekend — the honest answer separates bathroom-grade from showroom-grade.

Watch for: Particleboard boxes with raw cut-outs around the drain. Those edges drink leaks and collapse from the inside.

Map plumbing and electrical before the boxes land

Waste, supplies, outlet locations for shared baths, and any under-sink filtration decide cutouts and drawer layouts. Medicine cabinets may need wiring for integrated light or a mirror defogger. Measure emergence points with the old unit out when possible.

Watch for: Drawer vanity banks ordered without a pipe plan. Drawers and P-traps compete for the same cubic inches.

Prepare walls and floors — plumb, solid, dry

Cabinets telegraph waves in walls and dips in floors. Wall-hung pieces need blocking or frames. Install only after wet-area waterproofing and major moisture issues are resolved; cabinets do not dry a wet wall cavity.

Watch for: Hanging cabinets on a wall that still shows moisture meter readings from a previous leak.

Set, level, scribe and fasten into structure

Shim to level, scribe fillers to out-of-square corners, and fasten through hanging rails into studs or blocking — not only into drywall. Floating vanities get their full load path checked. Leave specified clearances for doors and drawers to open past toilets and towel bars.

Watch for: A unit racked to look tight against a bowed wall, so doors never sit right. Pack and scribe; do not twist the box.

Cut for plumbing cleanly and seal every cut edge

Open-back cabinets simplify this; closed backs need accurate openings. Seal cut particle edges, foam or grommet where appropriate, and keep shut-offs reachable without removing the stack of cleaning products with one hand.

Watch for: Giant ragged holes "for access" that destroy the cabinet's stiffness and invite pests and dust.

Install tops, medicine cabinets and towers as a system

Tops need correct overhangs and sealant at the wall. Medicine cabinets should be plumb at face height with doors that clear sconces. Linen towers must not block fan grilles, registers or future radiator access. Caulk where splash occurs; do not caulk ventilation paths closed.

Watch for: A medicine cabinet set so deep that the door hits the vanity light every time it opens.

Reconnect, test for leaks, and check door alignment after plumbing

After the plumber connects, fill the basin, run both supplies and inspect with a light under the cabinet. Re-tune doors and drawers after the top's weight settles. Hand over with shut-off locations shown to the homeowner.

Watch for: A visual "looks dry" check without filling the basin. Slow weeps appear under load.