Ask what fitted furniture is made of and you’ll often hear two answers: MDF and plywood. Both are man-made boards, both are widely used by furniture makers, and both can make excellent furniture. They behave differently, though, and the best pieces use each where it suits.
This guide explains what each board is, how they compare for strength, stability, painting and moisture, and how they’re used in wardrobes, shelves, kitchens and cupboards. It also says a little, in general terms, about other materials you may see mentioned, so you can make sense of quotes and product descriptions.
What MDF is
MDF stands for medium-density fibreboard. It’s made from fine wood fibres bonded together under heat and pressure into flat sheets. Because the fibres are fine and evenly spread, the board has no grain and no knots. It’s the same all the way through.
That makes MDF very stable. It doesn’t tend to warp, split or twist the way some other materials can. Its surface is smooth, so it takes paint well, and it can be cut and shaped cleanly, which suits doors with a moulded profile. Moisture-resistant grades are made to cope better with damp air, which is why we use them.
What birch plywood is
Plywood is made from thin layers of wood, glued together with the grain of each layer running at right angles to the one next to it. Crossing the grain this way makes the board strong and stiff in both directions, and stops it moving much with changes in humidity.
Birch plywood uses birch for the layers. It’s strong, holds screws well and is stiff over a span, which is why it’s good for long shelves, carcasses and drawer boxes. Its edge shows the layers as a series of fine stripes. That edge can be left on show as a feature, or filled and painted to match the rest of the piece.
MDF and birch plywood compared
| Moisture-resistant MDF | Birch plywood | |
|---|---|---|
| Make-up | Fine wood fibres, even all the way through | Thin layers of birch, grain crossed |
| Stability | Very stable, doesn’t warp easily | Stable, moves little with humidity |
| Strength and stiffness | Good, heavier for its strength | Very good, stiff over a span |
| Holding screws | Good with the right fixings, weaker in the edge | Very good, including near edges |
| Painted finish | Excellent, smooth surface | Good, may need more preparation |
| Shaping and profiles | Cuts and shapes cleanly | Less suited to moulded profiles |
| Edge | Plain, painted to match | Layered, shown or painted |
| Typical uses | Doors, panels, painted fronts, kitchens | Carcasses, long shelves, drawer boxes |
Where MDF works best
- Painted doors and panels. The smooth, even surface gives a clean painted finish, whether spray painted in the workshop or hand painted on site.
- Doors with a profile. MDF can be routed and shaped cleanly, so it suits framed or moulded doors in period rooms.
- Kitchens and damp-prone spots. Moisture-resistant grades suit kitchens, rooms next to bathrooms and units on external walls, where the air can be damper.
- Large flat areas. Side panels, end panels and plinths stay flat and true.
MDF is heavier than plywood for the same strength, and its edge doesn’t hold screws as well as its face. Good design and the right fixings deal with this.
Thinking about fitted furniture? We design, make and fit it across London: we visit, measure and talk through the design, then send a written quote. Arrange a design visit.
Where birch plywood works best
- Long shelves. Plywood is stiffer, so it resists sag better over a span. See our guide to depths, spans and sag.
- Carcasses. The boxes that form the body of a wardrobe or cupboard benefit from plywood’s strength and screw-holding.
- Drawer boxes. Drawers are pulled open and pushed shut many times a day. Plywood holds up well to that use.
- Where you want to see the edge. The layered edge can be a design feature on open shelving or a desk.
Why many pieces use both
It’s rarely a choice of one or the other. A typical fitted wardrobe might have birch plywood carcasses and shelves for strength, with moisture-resistant MDF doors and panels for a smooth painted finish. A bookcase might use plywood shelves for stiffness within an MDF frame painted to match the room.
Which board goes where is part of the design. We talk this through at the design visit, and the materials and finish are set out in your quote, so you can see exactly what each part is made of.
Other materials, in general terms
You may see other materials mentioned when comparing furniture. We don’t use them, but it helps to know how they behave:
- Solid timber is cut from the tree. It’s attractive, but it moves with humidity: it swells in damp air and shrinks in dry air, across the grain more than along it. Wide solid panels need to be built so they can move, or they may crack or warp.
- Particle board (chipboard) is made from larger wood chips bonded together. It’s common in flat-pack furniture. It’s usually covered with a printed or plastic surface, and it holds screws less well than plywood, especially if taken apart and refitted.
None of these is wrong for every job. They just behave differently, which is worth knowing when you compare quotes. Our guide to bespoke vs off-the-shelf furniture covers this from another angle.
Moisture, damp and external walls
No board likes standing water. Moisture-resistant MDF copes better with damp air than standard MDF, and plywood is stable in changing humidity, but neither should be fitted against a wet wall. Any damp should be put right before furniture goes in.
External walls in older London houses can be colder than internal walls, and condensation can form behind furniture. Ventilation behind and inside wardrobes on external walls helps. Read more in fitted furniture on external walls. If you’d like to talk about materials for your room, get in touch to arrange a design visit.
Quick answers
Is MDF weaker than plywood?
MDF is strong but less stiff over a long span and less good at holding screws in its edge. That’s why plywood is often used for shelves and carcasses, and MDF for painted doors and panels.
Is MDF suitable for a kitchen?
Moisture-resistant MDF is made to cope better with damp air, so it suits kitchens. Like any board, it should be kept away from standing water.
Can birch plywood be painted?
Yes. It can be painted all over, or the layered edge can be left on show as a feature. It may need a little more preparation than MDF for a very smooth finish.
Do you use solid timber?
We build with moisture-resistant MDF and birch plywood, finished by spray painting or hand painting.
Which board is better for bookshelves?
Birch plywood is stiffer, so it resists sag better over a span. The shelf’s span, depth and thickness matter as much as the board.
Related services
More advice
- Built-in Bookshelves: Depths, Spans and Sag
- Spray-Painted vs Hand-Painted Furniture
- Bespoke vs Off-the-Shelf Fitted Furniture
- Fitted Furniture on External Walls: Damp and Ventilation
- All advice
This guide is general information about fitted furniture. It isn’t legal, planning or building advice; for those, speak to the council, your landlord or managing agent, or a suitably qualified professional.