What is modified wood and why should you use it?

  • Small graduation cap icon Educational
  • Type/paper icon Article

Modified wood is incredibly popular in the timber industry today – it’s like standard timber’s older, stronger brother. The market demand for it is continuously rising, and it doesn’t look like it’s going to stop any time soon.

So, what’s the difference between wood that has been modified and standard timber? Well, the key difference is that modified wood’s characteristics have been changed thermally or chemically to enhance its properties.

What’s the process of modifying wood?


A piece of normal, untreated timber is taken and heated at up to 180 °C. The wood’s oxygen content is slightly stripped, which prevents it from burning at these high temperatures.

The absence of oxygen helps the cell walls of the timber go through changes which will make it a stronger, more dependable piece of timber.

Here’s a quick little guide to show you the step by step processes of each process:

  • Plato Process – This process puts water-saturated wood through hydrothermal treatment at 180°C
  • Les Bois Perdure – Freshly cut timber is dried out and then put in a heavily steamed environment
  • ThermoWood – The wood is steamed once more as a treatment after the high-intensity modification process


Throughout this process, different chemicals are introduced to strengthen and modify the timber, including hot oil, nitrogen gas and steam.

  • Acetylation – this is the process used to create Accoya An acetyl group is added to the timber’s compound structure, improving strength and durability
  • Retification – Wood is placed in a high nitrogen atmosphere with a very low oxygen content
  • Oil Heat Treatment – The wood is placed in an oil bath between 180°C and 220°C with some additional chemical additives which will alter and strengthen the wood

What’s the benefit?

There are countless benefits to chemically and thermally changing wood. Modified wood is stronger, longer-lasting and much more resistant to weathering or wear and tear. For these reasons, it’s the perfect material to use for big projects such as house building and construction, or for high-end woodworking, e.g. creating beautiful tables, wardrobes or doors.

These processes give you the option of using either hardwood or softwood, as thermally modified softwood carries similar properties to hardwood.

If you’re creating something that you want to last for a very long time, we’d suggest using modified wood.

Our modified timber products:

The modified products that we have in our arsenal include: Thermowood Redwood, Thermowood Radiata Pine, Accoya® and Medite Tricoya.

And that’s it!

So that’s how timber is modified, and why it’s seen as a superior wood! If you need some modified timber for your woodworking project, get in touch and we’ll help you out. If you want to have your say on our blog, or fancy having a timber-chat, tweet us!

Place your order online