Which interior door material is best for bathrooms and other wet areas?

For bathrooms, laundries and wet kitchens, use WPC, PVC or a properly sealed moisture-resistant engineered core — never raw MDF or unsealed particleboard. Look for a fully wrapped or sealed six-sided finish, a waterproof edge band, and stainless or coated hardware. Ventilation still matters: even waterproof doors last longer when the room is not permanently at 90% RH.