MDF for anything machined or painted — door panels, moulded edges, curved fronts. Plywood for anything that takes load at a joint or might get wet — sink bases, dishwasher housings, drawer boxes, structural backs. Most good kitchens use both, in different places.
The decisive difference is the edge: plywood holds a screw into the panel edge, MDF and particleboard do not.
Plywood performance is decided by the adhesive class, not the timber species. Interior, moisture-resistant and WBP look identical from the face.
MDF swells 8–15% in thickness after a 24-hour soak and never returns. There is no repair — the panel is replaced.
MDF machines and paints far better than plywood, whose veneer layers telegraph through a painted finish.
Plywood costs roughly 1.5–2× particleboard. Using it for every carcass panel is money spent where nothing is gained.
1. The edge is the whole argument
A cabinet is a collection of joints, and most of them are screws into a panel edge. Plywood has alternating grain layers, so a screw bites across the grain in several directions at once. MDF has a uniform fibre core, so the screw bites into a material that crushes rather than grips.
That single difference decides where each board belongs. Hinges on MDF doors are fine because the plate spreads load over the face. A drawer box that is screwed together at the corners is not — it needs plywood, or a mechanical joint.
| Property | Plywood | MDF |
|---|---|---|
| Screw holding, face | Good | Good |
| Screw holding, edge | Very good | Poor to moderate |
| Water tolerance | Depends on glue class | Poor unless MR grade |
| Machined profile | Tears, needs sharp tooling | Clean, holds detail |
| Painted finish | Veneer layers telegraph | Excellent |
| Relative cost | 1.5–2× particleboard | Similar to particleboard |
2. Water: three glue classes, not one product
Plywood is sold as one product and behaves as three. Interior grade uses urea-formaldehyde and is for dry conditions only. Moisture-resistant uses MUF and handles humidity. Exterior or WBP uses phenolic resin and survives boiling water.
The face veneer looks the same across all three, so the only evidence is the stamp or the mill certificate. If a supplier cannot name the class, assume interior grade.
| Class | Adhesive | Withstands | Use |
|---|---|---|---|
| Interior | UF | Dry conditions | Furniture, dry fit-out |
| Moisture-resistant | MUF | Occasional humidity | Kitchen and laundry carcasses |
| Exterior / WBP | Phenolic | Boiling water, weather | Sink bases, wet areas |
3. Finishing: why painted doors are MDF
MDF has no grain, so a painted finish sits on a uniform surface and stays flat. Plywood has veneer layers that expand at different rates when they absorb paint, and the layer lines show through within a season — especially on an edge that has been machined.
That is why painted shaker doors are MDF and why painted plywood edges need a lipping or a heavy band. If the design is a painted flat panel, MDF is not a cost shortcut, it is the correct substrate.
4. Cost per panel against cost per failure
Plywood at 1.5–2× particleboard looks expensive on a cutting list, and for standard carcass panels in a dry room it is wasted money — a melamine-faced particleboard box does the same job.
The calculation changes where failure is expensive. A sink base that swells has to be removed, which means disconnecting the sink and rebuilding the unit. A dishwasher housing that fails takes the adjacent cabinets with it. In those two locations, plywood is cheaper than the repair.
5. How most kitchens actually use both
A sensible specification uses particleboard or MDF for carcass panels, MDF for painted doors and drawer fronts, plywood for sink and appliance housings, and plywood for drawer boxes where the box is screwed rather than dowelled.
That mix gets the machining quality where it shows, the screw strength where it is needed, and the water tolerance only where water is plausible — rather than paying a premium across every panel to solve a problem that only exists under the sink.
| Component | Board | Why |
|---|---|---|
| Carcass panels | Particleboard or MDF | Flat, stable, cost-effective |
| Painted doors | MDF | Machines and paints cleanly |
| Sink base, dishwasher housing | WBP plywood | Tolerates a leak |
| Drawer boxes | Plywood, or dowelled MDF | Edge screw strength |
| Wardrobe back | 3–6 mm MDF or HDF | Stiffens the box, cheap |
Frequently asked questions
Is plywood better than MDF for kitchen cabinets?
Stronger at the edge and more water-tolerant, but harder to paint and 1.5–2× the price. Better in specific locations, not as a blanket upgrade.
Can MDF be used in a bathroom vanity?
Yes, with MR (moisture-resistant) MDF and sealed edges. Standard MDF will swell at the first unsealed cut.
What is WBP plywood?
Weather and boil proof — phenolic glue, suitable for exterior and wet applications. It is the only class that tolerates standing water.
Does plywood warp?
Less than solid timber, more than particleboard if the construction is unbalanced. An odd number of plies with the same species both faces stays flat.
Which is quieter, plywood or MDF?
MDF, noticeably. Its density damps sound, which is why speaker cabinets and some wardrobe backs use it.
