About Co2 Thermo Timber

Co2 Thermo Timber
Our ThermoTimber® is a thermo-treated wood produced using completely natural methods—heat and steam. The thermal treatment improves the wood’s properties, opening it up to a wide range of applications. Produced from premium quality, sustainable pine, spruce or redwood with no harmful chemicals, ThermoTimber® delivers high performance in any weather and with no oils/treatments applied will turn the traditional silver/grey as with all timber types.

Our ThermoTimber® is an environmentally sound alternative to pressure-impregnated wood and is resistant to demanding weather conditions, fungi and rot. Because of its decay resistance, low moisture content and thermal conductivity, Our ThermoTimber® is a dimensionally stable and durable wood product with improved insulation properties. ThermoTimber® keeps its shape and stands up to challenging climate conditions with recommended care and maintenance.

Our ThermoTimber® is a very popular choice for exterior cladding, decking, and facades and fencing. Because our ThermoTimber® is resin and pith free, you can easily apply glue, paint, oil finishing or surface treatments like a fire-retardant coating or simply leave it natural. Our ThermoTimber® is also an ideal material for interior panelling, flooring, furniture, and other building components. Due to its excellent properties, ThermoTimber® is also a popular choice for sauna interiors and exterior hot tubs.

ThermoTimber® Specifications

Applications:- External and internal cladding and decking - Fencing

Heat treatment classes:- Two standard thermal modification classes – Thermo-D and Thermo-S.

Durability:- Thermo-D is falling into durability class 2 (EN 350).

Resistance to rot:- Without additional treatments ThermoTimber® by is not resistant to termites.

Dimensional stability:- The thermal treatment process greatly reduces wood’s tendencies to warp, swell or shrink in different humidity conditions. The wood’s equilibrium moisture balance may be decreased to less than 40–50 % compared to untreated timber.

Thermal properties:- 0,09 W/(m K) according EN ISO 13787 + EN 12667

Resistance to fire:- D -s2,d0 according SFS-EN 13501-1:2018

Leaching:- As no substances are added during the ThermoTimber® process, no chemical leaching will occur. In addition, as the resin is removed during the process, the problem of resin leakage through the knots or pitch pockets is removed.

Ecological and safe:- ThermoTimber® is produced using high temperature and steam. Since no chemicals are added during the process ThermoTimber® contains only renewable substances. Disposal of offcuts can be burned or given into the normal waste system.


When selecting your timber type for your project it is worth taking in to consideration BS EN 350 timber durability class.

Durability is the ability of a species to resist decay either naturally or through preservatives. The Class is based on the ability of the heartwood (inner part of the tree) to resist fungal decay. The sapwood (the living outermost portion of the tree)is considered not durable and should not be used for external projects without preservative.

BS EN 350 has 5 classes of durability they are:-

Class 1 to 3 can be left as untreated timber, a natural ageing process will accrue e.g. Larch will turn a grey colour. Class 4 and 5 will need to be treated with preservatives.

For further information see www.greenspec.co.uk/building-design/cladding-durability-quality