MDF or solid wood? Choosing the right material for each part

Good bespoke joinery uses both. MDF for flat panels, painted doors and mouldings; solid timber for edges, frames, drawer boxes, worktops and anything that takes structural load or physical wear. Anyone insisting on one material for everything is selling a preference, not an engineering decision.

The distinction that matters is what each material does under stress: MDF is exceptionally stable but weak in the edges and vulnerable to water; solid timber is strong and repairable but moves with humidity.

MDF is engineered from wood fibre and resin, so it has no grain direction and effectively no seasonal movement across its width. That is why a 900-millimetre-wide painted panel in MDF stays flat while the same panel in solid timber would cup or split within a heating season.

Solid timber moves - typically a few millimetres across the width of a wide board between summer and winter. Good design accommodates this with floating panels in grooved frames, so the panel can move without opening a joint. Ignore it and you get cracked paint lines down every panel.

For painted work, MDF is simply better. It has no grain to raise, no knots to bleed, and machined mouldings come off the cutter crisp. Sprayed and lacquered MDF gives the flat, seamless painted surface associated with high-end cabinetry.

Solid timber under paint always shows some grain telegraphing and needs grain filling for a truly flat result. Where timber is the point - stained, oiled or waxed - solid or veneer is obviously the only option.

MDF holds screws poorly in its edges and can be crushed by an impact that solid timber would shrug off. It should not be used unsupported over long spans; a 600-millimetre shelf in 18-millimetre MDF loaded with books will sag noticeably within a year.

Solid timber, or MDF with a solid lipping, handles edges, arrises and load. That is why a well-made painted door often has an MDF panel in a tulipwood frame, and why a good shelf either has a solid front lipping or is thicker than you think it needs to be.

Standard MDF absorbs water and swells irreversibly. In bathrooms, utility rooms, boot rooms and around sinks, use moisture-resistant MDF and seal all cut edges, especially the bottom edges of plinths and door bottoms.

Even moisture-resistant board is not waterproof. Where standing water is likely - under a sink, in a wet room - solid timber, marine ply or a solid-surface material is the correct choice. Detailing matters as much as material: a properly sealed edge outlasts an unsealed premium board.

Cutting MDF creates very fine dust containing resin binders, and it should be machined with proper extraction and respiratory protection. That is one reason workshop-made and workshop-sprayed joinery is preferable to extensive cutting inside an occupied home.

Ask for low-formaldehyde board grades - E1 or better - which are standard from reputable suppliers and matter in enclosed spaces such as wardrobes and understairs cupboards.

MDF is cheaper per square metre than most hardwoods and much cheaper than walnut or oak. But labour usually dominates a joinery quote, so switching a whole project from solid timber to MDF rarely halves the price; expect a meaningful saving on materials and finishing, not a transformation.

The best value is normally the hybrid: MDF panels and doors in a tulipwood frame with solid lippings, sprayed. It looks like the expensive option, performs better than solid in a heated house, and costs less.

As a starting point for painted fitted furniture in a London home, the following division works well and is worth checking against any quote you receive.