Solid wood, plywood and MDF — what each is actually for

The honest answer to “is solid wood better” is that it depends what the panel has to do, and anyone who says otherwise is selling one of the three.

What actually separates them

Solid timber moves. It takes on and gives up moisture across the grain, expanding and contracting with the season. A well-made solid piece is designed to allow that movement — panels sit in grooves rather than being glued rigid, tops are fixed with buttons rather than screwed hard. When solid wood fails, it is almost always because someone stopped it moving.

Plywood is timber sliced thin and glued in alternating directions. That cross-graining is the whole point: it barely moves, and it holds a screw across the sheet reasonably well. It fails at the edges, where the layers are exposed, and it fails when it gets wet often enough for the glue to let go.

MDF is wood fibre and resin pressed into a board. It is dimensionally stable, perfectly flat, and takes paint better than anything else because it has no grain to telegraph. It has almost no screw-holding strength in the edge, and once it is properly wet it swells and never recovers.

Where each one belongs

For anything structural — a table base, a bed frame, a chair, a door — solid timber, because the loads go through joints and joints need material with strength in every direction.

For large flat areas inside a carcass — wardrobe sides, shelves over a moderate span, drawer bottoms, backs — good plywood, because it stays flat and does not need to move.

For a painted flat surface with no structural job — a shutter face, a panel infill — MDF is genuinely the correct choice, not a compromise. A painted MDF door will stay flatter than a painted solid one.

The question worth asking instead

Rather than asking what a piece is made of, ask what happens at the joints and edges, and what happens if the room gets damp. A wardrobe with a solid frame and plywood panels is usually a better object than one made entirely of either.

And ask what is under the finish. A great deal of furniture sold as “wooden” is MDF with a printed paper surface, which is a fine material honestly used and a poor one dishonestly sold.