Thermally modified wood is wood that is made more durable through a controlled heat process, without chemical additives. The result is a more stable, more sustainable wood variety with a warm colour and improved resistance to moisture and fungi. At Carpentier, this is known as HOTwood.
During thermal modification, wood is exposed to high temperatures of 160 to 230 °C, in an environment with steam and without oxygen. This heat treatment changes the chemical properties of the wood from the inside out.
The cell structure of the wood becomes more stable, so that it absorbs and releases less moisture. This makes the wood more resistant to fungi, wood rot and the effects of wind and weather. At the same time, the wood takes on a warmer, deeper colour that runs evenly through to the core.
Importantly: no chemicals or impregnation agents are involved. The treatment is entirely sustainable and the wood remains 100% recyclable.
HOTwood stands for Heated Outdoor Timber.
At Carpentier, ash is heated to at least 215 °C. This treatment gives the wood a durability comparable to tropical hardwood in durability class I, without any tropical wood being involved.
Carpentier applies thermal modification to various European wood varieties under the HOTwood brand name. Each wood variety has its own properties and application possibilities.
Thermo ash is the most widely used HOTwood wood variety at Carpentier. This wood variety has a refined appearance, achieves durability class I and comes with a 20-year guarantee on decking boards and cladding.
HOTwood softwood is available in two variants: pine (with knots) and Clear Pine (knot-free). Both have a warm appearance, a smart profile with good water run-off and a 15-year guarantee.
HOTwood bamboo is technically not a wood but a type of grass, yet it offers exceptional hardness and stability. Durability class I, FSC®-certified and a 25-year guarantee.
Abodo Vulcan® (Clear Pine) is a Radiata Pine from New Zealand, thermally modified using vertical grain technology. Exceptionally dimensionally stable and suitable for architectural façades.
Thermally modified wood is not necessarily stronger in terms of hardness, but it is more durable. It is more resistant to moisture, fungi and wood rot. The hardness may decrease slightly due to the treatment, but the dimensional stability and resistance increase significantly.
Less than untreated wood, but not entirely maintenance-free. Always treat the end grain with a wax oil during installation. Periodic cleaning and occasional re-treatment will further extend its lifespan.
Yes, thermally modified wood is specifically developed for outdoor applications. It is resistant to rain, sun and temperature changes and does not need additional impregnation.
Yes, like all other wood varieties, thermally modified wood weathers to grey over time due to UV radiation. With HOTwood, this greying process is more even than with untreated wood, without water stains or uneven discolouration. If you want to preserve the original colour, treat the wood with a suitable oil.
With impregnated wood, chemical substances are pumped into the wood to protect it. With thermally modified wood, the durability enhancement is achieved solely through heat and steam, without chemicals. This makes thermally modified wood more sustainable and fully recyclable.
Thermally modified wood is more expensive than untreated wood, but its longer lifespan and lower maintenance make it more cost-efficient in the long term. Moreover, you avoid the cost of regular maintenance or premature replacement.
Not sure whether thermally modified wood is the right choice for your project? Or would you like to know which HOTwood wood variety best suits your application? Our wood specialists are happy to help.
