How Long Do Timber Windows Last?

The Short Answer

Well-made timber windows last 60–100 years or more with proper maintenance. Many of London’s original Georgian sash windows are over 200 years old and still functioning. uPVC windows last 20–25 years. Aluminium windows last 30–45 years. No other window material comes close to timber for outright longevity.

Lifespan by Timber Type

What Kills Timber Windows Prematurely

Neglected Paint

Paint is not decorative on timber windows — it is the primary moisture barrier. Once the paint film cracks, water penetrates the timber, and rot begins within 2–3 years. The single most important thing you can do for your timber windows is repaint them on schedule. A maintenance coat costs £80–£150 per window and takes a day for a full house. Ignoring it for 5 extra years can mean replacing the entire window at £800–£2,000+.

Poor Original Timber

Cheap, fast-grown softwood with wide growth rings absorbs water more readily than slow-grown or engineered timber. Budget timber windows from the 1980s and 1990s are notorious for premature rot — not because timber is a bad material, but because the timber used was poor quality. Modern engineered redwood and modified timbers like Accoya have eliminated this problem.

Bad Detailing

Water collects on horizontal surfaces: sills, bottom rails, and meeting rails. If these areas are not properly sloped, drained, and end-grain sealed, standing water will find a way in. Good joinery design ensures every horizontal surface sheds water and every end-grain joint is sealed before assembly. We seal all end grain with a penetrating preservative before the first primer coat is applied.

Single Glazing with Putty

Traditional linseed oil putty hardens and cracks over time, allowing water behind the glass and into the timber. Modern double glazed units with factory-applied beading and sealed units eliminate this failure point entirely.

Maintenance Schedule

Check all windows annually in spring: look for cracked or peeling paint, failed putty, standing water on sills, and stiff operation. Sand and touch up any paint damage immediately — do not wait for the full repaint cycle. Full maintenance repaint every 8–12 years for standard coatings, or 12–18 years for Sikkens/Teknos microporous systems on Accoya.

Want timber windows built to last a century? Design yours in our 3D configurator and choose the timber, glazing, and finish that suits your property and budget.