Installation & Surface Treatment
Sharp tools are recommended throughout the processing of ThermoWood.
Nails and Screws
Acid-proof or stainless steel nails or screws are recommended for fastening of ThermoWood. Due to chemical changes in the wood, PH value changes and reacts strongly with other materials. The process also changes the cell structure of wood so that the strength of the attachment of the screw is reduced by approximately 20%. Using a nail-gun that enables adjustment of pressure is recommended. The nail must penetrate so that its head is aligned with the surface lining. The screws should be pre-drilled.
Normal water-or oil-based paints, oils and varnishes can be applied. Pigmented oil is recommended to maintain the woods original colour. Treatment of the end-grain is very important. The heat-treatment removes the resin from the pine and spruce. This, together with minimal movements, can extend the product’s life. The painting of ThermoWood should be done in accordance with the paint manufacturer’s recommendations, while paying special attention to proper protection, temperature and other weather conditions. The surface should be clean and dry during treatment. ThermoWood’s surface is not resistant to biological growth such as algae. These organisms derive their sustenance from the surrounding air and do no structural damage. To avoid these growths the wood must be treated at the time of installation by protective surface treatment. Carex Protim Natural and Brown-pigmented with added fungicides help prevent encrustation. Bitus Thermex decking should be oiled immediately after installation. Bitus is not responsible for mould or fouling caused by the external factors.
ThermoWood can be glued to get the same results as other conifers; follow the glue-manufacturer’s recommendations for best results. Longer pressing time is often required when bonding ThermoWood.
Normal efficient ventilation should be sufficient when installing ThermoWood mouldings. There should be an air-gap of at least 20 mm behind the coverage to enable vertical circulation of air.
The strength of ThermoWood is reduced by about 25% during heat-treatment. ThermoWood is not recommended for supporting construction. Much of the strength is lost in the knot structure; that’s why ThermoWood is sorted from the best raw material. There are research and studies that suggest that ThermoWood can be compared to class C14 according to the definition of EN 338.
Heat-treated decking is laid with a gap of 2-3 mm. This is to allow for expansion.