Two vanities can look identical in a photo and last very different lengths of time. The difference is what's under the finish. A bathroom is the hardest room in the house on furniture – steam, splashes, and the occasional leak under the sink – so the core material matters more here than anywhere else.
Particle board
Particle board is wood chips and sawdust pressed together with glue, usually covered in a vinyl or melamine skin. It's cheap and flat, which is why most big-box vanities use it. Its weakness is water: once water gets past the skin – at a cut edge, a screw hole or a chipped corner – the chips swell and crumble, and they don't go back. Screws also strip out easily, so hinges and drawer slides loosen over time.
MDF (medium-density fibreboard)
MDF is finer wood fibres pressed with resin. It's smooth and stable, which makes it popular for painted doors, and it's a step up from particle board. But it shares the same weakness: when water reaches the core, MDF swells, and the paint over it bubbles and splits. In a dry room that's rarely an issue. Next to a sink, it's a matter of when, not if. (We wrote more about this in why MDF centre panels fail in painted shaker doors.)
Plywood
Plywood is thin sheets of real wood glued in layers with the grain alternating. That cross-layered structure is why it's the material custom cabinet makers use:
- It handles humidity. It doesn't expand and contract the way solid boards can, and it resists swelling far better than MDF or particle board if it does get wet.
- It holds screws. Hinges and drawer slides stay tight for years.
- It's strong and lighter. A plywood box doesn't sag under a heavy quartz top.
No wood product is waterproof – wipe up spills and fix leaks promptly whatever you buy – but plywood gives you the most forgiveness.
Solid wood
Solid wood is beautiful and repairable, and it's what we use for face frames and legs. For large panels like cabinet sides and doors, solid boards can move with humidity, which is why quality vanities pair solid wood with plywood rather than using solid wood everywhere.
How to check before you buy
- Look at an unfinished edge – inside the cabinet, the back of a shelf, or the drawer box. Layers mean plywood. A uniform brown edge means MDF. Visible chips mean particle board.
- Ask what the doors are made of, not just the box. "Plywood construction" sometimes only means the cabinet sides.
- Look at the drawers. Dovetail joints in plywood or solid wood are a good sign. Stapled particle board drawers are not.
- Feel the weight. A heavy vanity isn't always better – particle board is heavy too – so combine this with the edge check.
What we use
Every Orca vanity has 3/4″ birch plywood cabinet boxes, solid wood face frames, doors and drawer fronts with a plywood core and real wood veneer, and dovetailed plywood drawer boxes on soft-close slides. No particle board. No MDF. See our real wood vanities.
Not sure? Ask before you buy. Text a photo of your space with your measurements to 778-994-4994 and we'll tell you which size fits, usually the same day. Or see the vanities in person at our Richmond showroom – Saturdays 11–4, weekdays by appointment.