Kensington Sash
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Wood Types &
Timber Species

We work with three timber grades - from cost-effective Engineered Redwood to ultra-stable FSC Accoya. Each is available across all our services and in all glazing and finish options.

Our three timber grades

Specified to your
project and budget.

We advise on the right timber at survey, taking into account your budget, the condition of the existing windows, the planning context, and the exposure of the installation.

SpeciesGradeDurability classTypical use
Engineered RedwoodStandardClass 3 (treated)All standard residential applications, period homes, budget-conscious projects. The most commonly specified option.
Red Grandis HardwoodPremiumClass 3–4Higher-specification projects, exposed or south-facing locations, premium painted and clear finishes.
FSC AccoyaSpecialistClass 1 (above ground)Demanding environments, maximum dimensional stability, long-term investment. 50-year above-ground durability guarantee.
In detail

Each timber explained.

Engineered Redwood
Standard

Kiln-dried and finger-jointed softwood with a stable, consistent profile and excellent paintability. The industry-standard choice for timber sash window manufacture - period-appropriate, widely available, and cost-effective. All our standard quotes are in Engineered Redwood unless specified otherwise.

Red Grandis Hardwood
Premium

A dense, durable hardwood with a rich grain that becomes more visible under light-coloured and clear finishes. More resistant to moisture movement than Redwood - a good choice for exposed locations, south-facing elevations, or projects where the client wants a premium material throughout. Available in all our products.

FSC Accoya
Specialist

Acetylated Radiata Pine - a softwood modified at the molecular level to become dimensionally ultra-stable and highly resistant to rot, insects, and moisture. It will not swell, shrink, or warp even in extreme conditions. Carries a 50-year above-ground durability guarantee. FSC certified. The best long-term investment for demanding installations.

Get started

Every property is surveyed in person - no estimates from photos, no hard sell.