Aluminium vs timber windows

This comparison usually comes up for one of two reasons: a period property where timber is the original material, or a conservation area where someone has been told timber is the only option.

Maintenance is the real difference

Timber needs recoating every three to five years, sooner on an exposed elevation, and if that maintenance lapses the timber itself starts to go. Aluminium needs washing. Over a thirty-year life that difference is substantial in both money and attention.

Where timber genuinely wins

Repairability. A timber window can be spliced, filled, re-planed and refinished more or less indefinitely. An aluminium frame is a manufactured unit — economically repairable in its hardware and glass, but not in its extrusions.

Authenticity. On a listed building or in a tightly controlled conservation area, timber may be the only material that will be consented, and no amount of engineering argument will change that.

Warmth of appearance. Subjective, and real. Painted timber has a depth that powder coat does not quite reproduce.

Where aluminium wins

Slimmer than timber for the same structural performance, especially on large openings. Dimensionally stable — it does not swell in a wet winter and stick. 30 to 50 years with a 25-year finish guarantee and effectively no maintenance.

Conservation areas and Crittall style

This is where the conversation has changed. Slim aluminium profiles with fine glazing bars — Crittall style — replicate the steel windows of the 1920s and 30s convincingly, and conservation officers increasingly accept them where a chunky uPVC frame would be refused outright. On an interwar or industrial-conversion property that is often the correct answer historically as well as practically, because the original windows were steel, not timber.

Never assume, though. Check the specific consent or Article 4 direction before ordering — some specify sightlines and glazing bar profiles, not just material.