Bathroom cabinetry is among the most practical furniture you can build yourself, and also one of the most unforgiving environments for timber. Get the material choice and finishing right and your cabinets will look sharp for 15 years. Get it wrong and you will be dealing with swollen doors, delaminating MDF, and mould-stained timber within 12 months. This guide covers two builds that together transform a bathroom: a wall-mounted medicine cabinet with a mirror door, and a floor-standing vanity cabinet in Shaker style.
Project 1: Wall-Mounted Medicine Cabinet
A recessed medicine cabinet — one that sits in the wall cavity between studs — is the gold standard, but cutting into walls requires locating studs, checking for wiring, and patching drywall if things go wrong. A surface-mounted cabinet gives you 90% of the storage with none of the wall drama. This design is 500mm wide × 700mm tall × 150mm deep: deep enough for most bathroom products, wide enough to hold a proper mirror door.
Medicine Cabinet Cut List
| Part | Qty | Dimensions (mm) | Material |
|---|---|---|---|
| Top and bottom panels | 2 | 500 × 150 × 18 | MR MDF or solid pine |
| Side panels | 2 | 664 × 150 × 18 | MR MDF or solid pine |
| Back panel | 1 | 500 × 664 × 9 | MR MDF or ply |
| Adjustable shelves | 2 | 464 × 130 × 18 | MR MDF or solid pine |
| Door frame top/bottom | 2 | 500 × 40 × 18 | Solid pine |
| Door frame sides | 2 | 700 × 40 × 18 | Solid pine |
| Mirror glass | 1 | 424 × 624 × 4 | Float glass mirror |
Outer dimensions: The carcass assembles to 500mm wide × 700mm tall × 150mm deep. The door hangs on the face of the carcass and sits proud of the wall surface by 18mm (door frame thickness). Overall projection from wall: approximately 170mm.
The Waterproofing Challenge
Standard MDF — the most common sheet material for painted cabinetry — absorbs moisture readily and will swell, delaminate, and lose its integrity in a bathroom. You have two solid options:
Moisture-Resistant (MR) MDF: Identifiable by its green core colour when cut. MR MDF is designed for humid environments and resists swelling under normal bathroom use. It is not waterproof — direct water contact will still damage it over time — but for a wall-mounted cabinet that stays dry on the outside, it is the correct and cost-effective choice. It machines, sands and paints exactly like standard MDF. Available at most major timber suppliers and Bunnings in most states.
Solid pine with sealed surfaces: Solid timber handles moisture cycling better than any sheet product, provided all surfaces — including the back face, edges, and inside — are fully sealed. Use a shellac-based primer (Zinsser BIN) followed by two coats of semi-gloss water-based enamel on every surface before assembly. Unsealed timber in a bathroom cabinet will absorb moisture vapour through the unpainted back face and start to warp within months.
Mirror Sourcing: Glazier vs Mirror Tiles
Do not use adhesive frameless mirror tiles for a medicine cabinet door. The joint lines will never align perfectly, the tiles look cheap, and they delaminate over time in humid environments. Instead, have a single piece of float glass mirror cut to size by a glazier or glass supplier. The cost is modest — a 424×624mm piece of 4mm silvered mirror glass typically runs $40–$70 depending on your location. Specify “float glass mirror, 4mm, bevelled edge” and they will cut it to your exact dimensions with a clean, polished edge.
Fix the mirror to the door frame using mirror adhesive (Selleys Mirror Fix or equivalent — not standard silicone, which contains acetic acid that attacks the silver backing) and 4 small mirror clips at the corners for security.
Assembly Steps
- Cut all carcass panels. Seal all surfaces with MR primer or shellac primer before assembly.
- Glue and screw the top and bottom panels between the side panels. Use 60mm screws from outside faces. Pre-drill and countersink all holes.
- Pin and glue the back panel into the rebate at the rear of the carcass. This keeps the box square while the glue sets.
- Drill shelf-pin holes in the side panels for adjustable shelves. Use a shelf-pin jig for consistent spacing.
- Build the door frame by joining the four frame pieces with pocket holes (two per corner). Check it is square and flat. Allow the glue to cure flat on the bench.
- Once the door frame is cured, bond the mirror glass using mirror adhesive. Allow 24 hours before hanging.
- Hang the door on the carcass using two 35mm concealed hinges (Blum Clip-top or equivalent). Adjust the hinges for a flush, even gap all around.
- Apply two final coats of semi-gloss water-based enamel to all visible surfaces. Sand lightly between coats with 240-grit.
- Mount to the wall through the back panel into studs, or use appropriate hollow-wall anchors if mounting between studs.
Project 2: Floor-Standing Vanity Cabinet (Shaker Style)
A floor-standing vanity cabinet supports the basin or countertop above it. This design uses a plywood carcase — structurally stronger and more moisture-resistant than MDF — with a solid pine face frame in classic Shaker style. The under-bench space provides storage for cleaning products and spare towels.
Standard Vanity Dimensions
Australian vanity heights sit between 850mm and 870mm (bench to floor), matching standard kitchen bench heights so you can use plumbing fittings interchangeably. Width is typically 600mm, 750mm, 900mm or 1200mm depending on bathroom size. This build is 900mm wide × 870mm tall × 450mm deep — a common single-basin size.
Carcase Construction
Use 18mm structural plywood for the carcass panels (sides, top, bottom, shelf). Ply is dimensionally stable, holds screws well at edges, and handles the occasional wet wipe-down far better than any sheet product containing paper-based core material. Cut all panels, seal the exposed ply edges with an iron-on or glued timber edge strip, and assemble with 60mm screws and construction adhesive. A simple biscuit joint or pocket hole connection at each panel intersection provides sufficient alignment and strength.
Face Frame
The Shaker face frame is a simple grid of solid pine rails and stiles (horizontal and vertical frame members) glued and pinned to the front face of the plywood carcass. Standard face frame stock is 45mm wide × 20mm thick. Join the stiles and rails with pocket holes before attaching the frame to the carcass. The face frame covers all exposed ply edges and creates the door opening.
Sink Hole Cutting
If you are fitting a drop-in or undermount basin, you need to cut a hole in the top. The basin manufacturer will supply a paper or cardboard template — use this, not your own measurements. Trace the template onto the bench top, drill a starter hole inside the cut line, and cut with a jigsaw. For laminate or solid timber tops, run masking tape along the cut line to prevent chipping. Smooth the cut edge with 80-grit sandpaper and seal immediately with polyurethane.
Finish Options
2-pack lacquer: The most durable bathroom finish available in a spray can — some auto paint suppliers stock 2-pack clear in rattle cans. Extremely hard, water-resistant, UV stable. Requires a respirator during application due to isocyanate content in the hardener. Best if you want a perfectly smooth, almost plastic-like surface.
Semi-gloss water-based enamel: The practical DIY option. Dulux Aquanamel or Taubmans Endure in semi-gloss will hold up well in a bathroom when applied over a suitable primer. Apply 2–3 coats. Re-coating when worn is straightforward. Suitable for both MR MDF and solid timber.
Both cabinets, built over a weekend, will cost approximately $180–$280 in materials depending on timber quality and mirror size — a fraction of the cost of comparable store-bought units.
Want Full Plans for More Builds?
If you are fitting out a whole bathroom or want to keep building around the house, Ted’s Woodworking gives you instant access to over 16,000 detailed woodworking plans — with cut lists, diagrams, and step-by-step instructions for everything from small bathroom cabinets to full kitchen renovations.
