We strive to offer the latest advances in timber window, door and shutter technology and materials. We are pleased to provide offer the Accoya® modified wood as part of our timber materials.

In this and the following 3 posts, we will outline the principles of the Accoya® wood modification process, properties of Accoya® wood and its increasing number of applications.

Modified wood is a term used to describe wood whose molecular composition has been altered, normally by chemical or thermal processes. This differs from a conventional preservative treatment where wood is impregnated with a biocide. An increasing range of modified wood products are available in the UK and it is essential, when specifying, that they are considered individually because their properties vary considerably.

Accoya® is the brand name of wood that has been modified by acetylation. This modification process replaces the water binding sites in the wood cell wall with acetyl groups that do not bind with water. These acetyl groups occur naturally in wood, albeit at much lower levels than in Accoya® wood.

Although Accoya® wood has only been on the EU market since April 2007, research on acetylated wood began as early as 1928. For this reason there is a wealth of knowledge on the performance of acetylated wood.

Acetylation significantly improves several wood properties. It increases durability of both sapwood and heartwood, and makes timber more dimensionally stable. For these reasons, Accoya® wood offers many advantages over unmodified wood. Some properties, such as ease of processing, strength, adhesion and ease of fixing, are relatively unaffected.

Radiata pine is the wood species presently used to manufacture Accoya®, although the process has proven effective on a range of other softwoods and hardwoods.The radiata pine is sourced sustainably and, since acetylated wood may be re-used, recycled and disposed of without the risks of environmental damage, Accoya® offers an alternative to using preservative treated wood (or increasingly scarce naturally durable timbers) for applications where there is a risk from decay.



Accoya is becoming widely recognised as the number one timber in the production of high quality timber windowsdoors and shutters.

Whilst we have been working with this timber for some time, we asked the UK management team to come and see the staff at our factory for a training day. This covered (and confirmed) best practice on all aspects of using Accoya.

We can tell you in great detail why Accoya is ideal for use in external joinery, but in summary:

Durability: Class one durability, comes with a 50 year anti rot warranty

Dimensional stability: reduces selling and shrinkage by up to 75%, meaning paint finishes last 3-4 times longer than on conventional timbers

Environmental credentials: FSC certified, improved thermal performance, can be safely recycled and long product life

It may not be the cheapest of timber and this is why many companies will not use it. The result is invariably a product that is still susceptible to rot. At Timeless we look to offer the best possible performance from our products – this means using the best possible materials and that is why Accoya is used for the majority of our timber window and products.

At Timeless we can manufacture all types of folding timber shutters to compliment your windows. We take pride in the fact that all our internal shutters are to bespoke designs and are custom-made. Where necessary, we can create exact replicas of shutter doors and panels, matching materials and profiles as required. We construct and install shutters using traditional methods, creating a stunning feature for any room, as beautiful as any piece of furniture and enhancing the look of your timber windows or doors.

As well as providing a detail that is very pleasing to the eye there are other benefits of fitting internal timber shutters to your sash or casement window:

  • Shutters offer tremendous improvements to the thermal and acoustic performance of the existing window.
  • Timber shutters will typically replace the need for curtains in a room, giving privacy to the room or blocking the light out completely.

See some photos of numerous shutter projects completed by us.

An ever increasing order book and our desire to consistently produce products of the highest quality triggered our requirement to create a larger spray area. Planning of the new unit was carefully considered in terms of size and specification, and we are particularly grateful for the expertise received from the guys at Teknos (our paint suppliers) to get the best out of our investment.

Timber wood shutter door decorating

The new spray area is insulated to reduce heat loss, and propeller fans assist air movement throughout drying area in tandem with heaters – Thermostatically controlled to a constant temperature. The spray area gives us an optimum, controlled environment to ensure our products can be finished to the highest possible standard at all times.

Less time in the paint shop and output to a more consistent standard helps to keep our delivery times down, allowing us to get new windows into your home rather than sitting in our factory.

For further information or to arrange a free, no obligation survey, please call us on 020 7061 6262 or Contact Us via email. We would be delighted to discuss your requirements for: