Thermowood – Thermal Treated Decking Product Data Sheet COSHH MSDS Information

Thermowood – Thermal Treated Decking Product Data Sheet COSHH MSDS Information

Thermowood – Thermal Treated Decking Product Data Sheet COSHH MSDS Information


Thermowood – Thermal Treated Decking Product Data Sheet COSHH MSDS Information

Thermowood – Thermal Treated Decking Product Data Sheet COSHH MSDS Information

Pine : Scots pine (Pinus sylvestris) European Redwood ThermoWood

Origin of Timber Scandinavia

Durable Use Class 2 UC3

Minimum Service Life 25 years

ThermoWood or thermal modified / heat treated timber is a natural wood product without any chemical additives. ThermoWood waste can be handled as with any other untreated wood waste. The material is bio-degradable and can be disposed of at the end of its service life by either burning or placing into the normal waste system. In most cases energy needed for the ThermoWood process is produced by burning wood biomass fuels. Additional energy is provided with solutions such as natural gas. Energy is needed mainly for drying, which accounts for 80 percent of the heat energy used. The production of ThermoWood consumes about the same amount of electricity as is used in normal kiln drying of sawn timber. 

Our thermal treated timber conforms to the Government Timber Procurement Policy and the European Timber Regulation EUTR, we supply mainly PEFC Certified ThermoWood for Redwood and Whitewood, FSC for Hardwoods.

FSC Certification No. TT-COC-003944.229     PEFC Certification No. BMT-PEFC-1119.229

Thermal Modification Process

Heat treatment involves heating wood material to a temperature of 180–220 °C while at the same time protecting it with steam.

The steam protects the wood, but it also influences the chemical changes taking place in wood.

100% natural – only heat and steam are used in the manufacturing process and no chemicals are added.

Thermally modified wood is an environmentally friendly and fully recyclable product, the manufacture of which does not include any harmful chemicals.

Thermo treated wood remains dimensionally stable as equilibrium moisture content is also permanently reduced.

After thermal modification, the moisture content of the wood decreases to around 4-6 percent. As a result of this lowered equilibrium moisture content, thermally modified wood does not react to changes in humidity as drastically as untreated wood.

The seasons change – better than corresponding untreated or chemically treated wood.

The dimensional stability of wood due to varying air humidity clearly decreases in heat treated products. This is due to the reduction of wood shrinkage, lower equilibrium moisture content and slower absorption of humidity because of heat treatment.

The higher the heat treatment degree is, the more the dimensional instability of thermally modified wood is reduced.

During treatment the cells of wood are modified and that causes the changes in wood characteristics:

  • the colour darkens, new colour is from light brown to very dark brown
  • equilibrium moisture content is reduced 20-50%
  • increased dimensional stability
  • decreased water absorption
  • less deformations and tensions caused by humidity changes
  • heat conductivity lowered up to 20-30%
  • wood density decreases
  • resin is removed from the wood during the thermal modification process

Thermowood Decking Maintenance and Care

Is it important to apply a decking oil with UV properties that is pigmented e.g. Brown UV Osmo decking oil. The surface oil treatment of the decking extends the life of the wood and improves the use of the decking, so we recommend a surface treatment or oil. Untreated ThermoWood decking will turn grey in time, because of the UV light and other weathering processes.

Most external wood treatment decking oils can be used on ThermoWood.

We recommended decking to be treated or oiled immediately after installation so that the surface is immediately protected from moisture and dirt and no separate cleaning is required before handling. The service oil of the decking should be done every two years or more often depending on the conditions and the use of the decking.

 Air impurities such as soot or pollen in the air sometimes might cause small black spots on the surface of the decking.  In some cases, strong decking base (iron particles) combined with water can colour the wood. You can prevent black spots by using pigmented decking oil right after installation. The black spots will mostly disappear over time as the boards turn grey, if the decking is left untreated. Always try small test areas before treating a complete deck.

The black spots can be removed by following these instructions:

  • Remove (brush) all loose material away from the surface using a firm brush
  • Wash and clean the surface using a spot removal liquid wood reviver. Rinse well and let the surface dry. If the surface has a clear film after washing, remove it before continuing.
  • Sand using a fine sand paper if needed.
  • Oil the decking 1-2 times with pigmented decking oil using a thin brush or sponge. Spread evenly and with continuous movement for the entire length of the board to avoid overlapping. Wipe excess oil off immediately. Apply the next layer after the previous one has dried.

For Timber and Wood Products COSHH  / MSDS information

 Solid Timber

Solid timber is not in itself a hazardous substance.  Contact with wood therefore does not create any health risk under normal use, although some timbers may cause skin irritation or dermatitis to sensitised individuals.  

A simple ‘risk assessment’ should be carried out before solid timber is handled.  Normally, the conclusion will be that the risk of a hazard to health is ‘negligible’.

However, there are occupational hygiene standards for exposure to dusts derived from the processing of timber, and these are outlined below.

Hardwood Dust

This is given a Maximum Exposure Limit (MEL) and a OES (Occupational Exposure Standard) in the COSHH Regulations which should not, in normal circumstances, be exceeded.  It is given as a weight of material per cubic metre of air, time weighted over a reference period of 8 hours.

Hardwood dust is also defined as a carcinogen within the Regulations.

The COSHH Regulations impose a duty on employers to take all reasonable precautions and to exercise all due diligence to ensure that exposure is kept as far below the MEL/OES as is reasonably practicable.

The limit is 5mg/m3 based on an 8-hour TWA (Time weighted average).

Softwood Dust

Softwood dust has also been assigned a MEL/OES in the 1996 amendment to the COSHH Regulations.  The MEL/OES has been set the same as Hardwood dust at 5mg/m3 based on an 8 hour TWA.  The duties as above apply.

Note: Timber users should be aware that if timber is worked so as to produce dust, and that dust is present in concentrations above the levels laid down, it will constitute a hazardous substance.

Joinery Components

Most joinery or trim components treated or otherwise, should not require hazard data sheets under most circumstances of use.


The main hazard is fine particles or dust since these can be inhaled.  Therefore, ways of reducing this route should be sought. The previously indicated MEL/OES should be used.

Dustless cleaning and handling should be a priority; however, in some circumstances, respiratory protection and personal protection may have to be used.

 Alternative Processes

Traditional methods of shaping, cutting or forming of timber have been used for many years and the risks are known.  New machines are often accompanied by built-in dust extraction devices (local exhaust ventilation, LEV), which deal with the major risk of inhalation of dust.  These should be inspected and maintained as per Regulations. When measurement is necessary so as to be sure that LEV is working correctly and the MEL (Maximum Exposure Limit) and OES (Occupational Exposure Standard) is not being exceeded.

New methods of cutting, involving such devices as lasers, are now being introduced.  These do not tend to produce dust, but fumes.  At present there is little known about the toxic hazards of such fumes, and careful discussions with the equipment supplier should take place where these machines or processes are used.

For toxic woods refer to Government HSE  guidance: https://hlfqvz1lxnty.wpcdn.shift8cdn.com/wp-content/uploads/2019/02/wis30-HSE-Toxic-Woods-Timber-Focus.pdf


Please note we are experiencing delivery delays on orders due to increased demand and COVID-19.

However, we are still processing all orders as fast as we can.