Timber types for joinery: choosing the right wood for the job

Hardwood and softwood are botanical categories, not hardness ratings. Balsa is a hardwood; yew is a softwood harder than some hardwoods. What matters for joinery is density, stability, grain, durability and how the timber takes a finish.

The other essential factor is moisture content. Timber for internal joinery in a centrally heated London home should be kiln-dried to around eight to ten per cent. Timber at fifteen per cent will shrink after installation and open every joint on the piece, no matter how well it was made.

European oak is the default choice for visible hardwood joinery: strong, durable, with a pronounced grain that reads well on doors, stair parts and worktops. Quarter-sawn oak shows the characteristic medullary flecking and is more stable than plain-sawn.

It does have quirks. Oak is high in tannin, so it reacts with ferrous fixings and with damp, causing black staining - use stainless or brass fixings. It also darkens and ambers over time, so a new oak piece will not match a twenty-year-old one until it has aged.

European and American black walnut are the premium choices for furniture-grade cabinetry: fine, even texture, chocolate-brown with purple and grey notes, and a superb surface under oil or lacquer. It machines beautifully and is stable for its density.

It is expensive and it lightens rather than darkens with light exposure, so avoid designs where a section sits permanently in shadow next to a sun-exposed panel. Walnut veneers allow the look across large panels for far less than solid.

Ash is pale, tough and springy with a strong straight grain, and it stains and dyes exceptionally well - it is often the timber behind fashionable smoked, greyed and blackened finishes. Maple is finer and creamier with a subtle grain that suits contemporary cabinetry.

Beech is dense, even and inexpensive, which makes it excellent for drawer boxes, internal frames and worktops, but its grain can be bland on show faces and it moves more with humidity than oak or ash.

Tulipwood, sometimes sold as American poplar, is the workhorse of painted hardwood joinery. It is stable, straight-grained, takes paint superbly and is much cheaper than oak. Most high-quality painted doors, frames and mouldings are tulipwood rather than pine.

European redwood - what most people call pine - is the standard softwood for painted structural joinery, studwork and stairs. Choose slow-grown, kiln-dried, knot-controlled stock; cheap pine with large knots will bleed resin through paint for years.

For external joinery - doors, windows, gates - durability matters more than looks. Sapele and idigbo are common choices in the UK for their moderate durability, stability and cost. Accoya, an acetylated softwood, is more expensive but exceptionally stable and long-lasting for painted external work.

Whatever the species, external joinery needs end grain sealed, all faces primed before assembly where possible, and a maintenance schedule. Timber does not fail because it is timber; it fails because a paint film cracked and nobody noticed.

Most bespoke cabinetry uses sheet materials for carcasses and panels because they are dimensionally stable across large areas. Birch ply gives a strong carcass with an attractive exposed edge. Veneered MDF gives the look of solid hardwood on a flat, stable panel and is standard for high-end cabinetry.

Veneer is not a compromise on quality; it is how large flat hardwood surfaces have been made for centuries. The quality markers are veneer thickness, whether leaves are sequence-matched across adjacent doors, and how the edges are lipped - a solid timber lipping protects the corner and allows a proper arris.

Ask for FSC or PEFC certified timber. It is widely available in the species above and costs little more. Avoid uncertified tropical hardwoods, and be aware that some species are subject to trade restrictions.

Reclaimed timber can be excellent, particularly for character pieces, but it needs careful selection: old nails ruin cutters, and reclaimed stock is often at an unpredictable moisture content that must be conditioned before machining.