Accoya is our first choice for our timber windows and doors, being at the cutting edge of wood science. Not only is it thermally efficient, it is more durable and dimensionally stable than the best tropical hardwoods. Accoya is an environmentally friendly solution to the problem of the deforestation of slow-growing redwoods and hardwoods.

What is Accoya timber?

Made from sustainably sourced softwood, Accoya undergoes a unique modification process that transforms its molecular structure, enhancing its natural properties without the use of toxic substances.

The process, known as acetylation, involves treating the wood with acetic anhydride derived from acetic acid. This reaction converts the free hydroxyl groups within the wood into acetyl groups, significantly reducing its ability to absorb water. As a result, Accoya wood becomes highly resistant to rot, dimensional stability is greatly improved, and its durability is enhanced.

To produce Accoya, only abundantly available wood species are used from certified, sustainably managed forests and plantations.

The benefits of Accoya for windows and doors

Here are the key reasons why at Timbawood we choose Accoya for our sash windows, casement windows and timber front doors:

1. Stable and durable

First and foremost Accoya is strong and stable, so it won’t swell, twist or warp. It is often used in the construction of bridges because of its stability in damp conditions.

The durability of Accoya is Class 1 (EN350), which is the highest durability class possible, and is guaranteed to last 50 years above ground.

This means that windows and doors will open effortlessly all year round, and there will be reduced maintenance costs with less need for repainting.

Accoya’s expected service life of 77 to 90 years is not only superior to regular timber but also to aluminium and PVC windows.

2. Thermally efficient

Accoya timber is naturally insulating, and offers improved insulation in comparison to commonly used hardwood and softwood species.

Accoya timber window frame

3. Sustainable

Unlike other timbers, the Accoya wood manufacturing process is non-toxic and adds nothing to the wood that does not already naturally occur within it.

Accoya timber is manufactured from trees that are fast growing and abundantly available – which means there is a consistent supply without the deforestation of tropical forests that comes from using slow growing hardwoods.

Unlike hardwood which has a poor carbon footprint, Accoya window frames are actually assessed to be carbon neutral over their full life cycle, due to low emissions during production, their long lifespan and recyclability.

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