How to Choose the Right Timber for Home Projects

Start With Where the Timber Will Live

The first question to ask about any piece of timber is not what it looks like, but where it is going to live. Wood moves as it takes on and loses moisture, and how much it moves depends on the conditions around it. Joinery in a centrally heated room will settle at around 8–10% moisture content, while timber outdoors through a British winter can climb well past 20%. That difference of a few per cent is enough to turn a snug mortice and tenon into a rattling joint, or to split a wide panel that was fitted too tightly.

For interior work — shelves, skirting, fitted wardrobes, stair parts — you want kiln-dried stock that is already close to the humidity of the room it will end up in. For exterior work, you need timber that is either naturally durable or pressure-treated, because damp plus mild temperatures is exactly the recipe for rot. Get this first decision right and almost everything else falls into place.

Softwoods: The Everyday Workhorses

Softwoods come from conifers, grow quickly and cost far less than hardwoods. For most home carpentry they are the sensible default.

• Scots pine, redwood and whitewood: the familiar stuff from the timber merchant. Easy to saw, plane and paint, and perfectly good for studwork, shelving, painted furniture and interior framing. Not durable outdoors unless treated.
• Douglas fir: stronger and more stable than pine, with a warm pinkish tone. A solid choice for exterior joinery such as door frames and garden structures, and it takes a finish well.
• European larch: durable heartwood that performs well for cladding, decking and garden timber. Harder to work than pine, but it weathers to a handsome silver-grey.
• Western red cedar: lightweight, very stable and naturally durable, which makes it superb for cladding, shed doors and anything that needs to stay straight outside. It is also the most expensive of the group.

Check for PAR (planed all round) stock if you want to avoid wrestling with rough sawn boards, and remember that planing removes a few millimetres from every face.

Hardwoods: Worth the Investment

Hardwoods come from broadleaved trees. They are slower grown, denser and pricier, but for furniture, worktops and anything on show, they earn their keep.

• Oak: the classic British choice. Strong, durable and beautiful, inside and out. Be aware that oak reacts with steel fixings and can leave dark stains, so use stainless or galvanised screws and nails.
• Ash: tough and springy with a bold grain, ideal for chairs, tool handles and hard-wearing furniture. Keep it indoors.
• Tulipwood: a stable, fine-grained hardwood that paints beautifully and is often sold as a cheaper alternative for interior joinery and painted furniture.
• Beech: hard, close-grained and excellent for worktops and chopping boards, though it moves noticeably with changes in humidity.
• Sapele and iroko: dependable exterior hardwoods for windows, doors and sills. Iroko is oily, so wipe surfaces with solvent before gluing.
• Walnut: rich, dark and decorative — a furniture timber rather than a structural one.

Strength, Stability and Grain

If a piece of timber is carrying load, buy it graded. Structural softwood is marked C16 or C24, and those numbers tell you the bending strength you can rely on. Span tables will tell you what size joist or rafter you need for a given distance. Never guess a span, and never substitute a smaller section because it fits the gap more neatly.

Grain direction matters just as much. Timber cut quarter-sawn is more stable and less prone to cupping than flat-sawn boards, which is why it is favoured for wide panels and table tops. Large knots, checks and splits weaken a board, so sight along every length before you buy. Wherever possible, let wider boards move: fix them with slotted holes or buttons rather than pinning them rigidly on all four sides.

Sheet Materials and What They're For

• MDF: smooth, uniform and cheap for painted panels, plinths and mouldings. Use the moisture-resistant version (usually with a green core) in kitchens and bathrooms.
• Plywood: layers glued crosswise make it strong and stable. Choose exterior-grade (WBP) for damp areas, and birch ply when you want the edges on show.
• Chipboard and melamine-faced board: fine for carcasses and budget shelving, but the edges are fragile and swelling is permanent once water gets in.
• OSB3: rough-looking but strong and moisture-tolerant — ideal for sheathing, flooring and workshop jigs where appearance does not matter.

Finishing, Budget and Buying Wisely

No timber is maintenance-free. Painted joinery needs a primer, an undercoat and a topcoat, with end grain sealed first because it drinks paint faster than the faces. Oiled and waxed surfaces suit oak and worktops, but they will need refreshing every year or so. Exterior timber needs a breathable finish that lets moisture out rather than trapping it in.

Buy from a proper timber merchant where you can sort through the stack and ask about moisture content and origin. Order around 10% more than you need to allow for defects and mistakes. Store boards flat, off the floor, in the room where they will be used for a week or two before cutting. It is a small delay that saves a great deal of grief later.

Finally, be honest about the job. If it is hidden, structural or temporary, save your money. If it will be seen and touched every day, buy the best species you can afford — good timber is the cheapest part of almost any project when you count the hours you put into it.