Thermally modified timber as durable wood for exterior applications: Background and properties

Sini Metsä-Kortelainen, Pertti Viitaniemi

    Research output: Contribution to conferenceConference articleScientific


    An industrial-scale thermal modification method for wood has been developed in Finland at VTT together with Finnish industry. The Finnish thermal modification method is based on heating the wood material for a few hours at high temperatures over 180°C under normal pressure while protecting it with water vapour. Thermal modification changes the chemical and physical properties of wood. During thermal modification the colour of wood darkens, the dimensional stability enhances, equilibrium moisture content reduces and the biological durability increases. On the other hand, as a result of thermal modification, the wood becomes more brittle and bending and tension strength decrease in relation to the level of heat-treatment. Thermally modified wood is used in many applications, where enhanced dimensional stability and biological durability are required. Also, the brown colour of the thermally modified wood is experienced as a benefit in furnishing. There are plenty of good experiences of using thermally modified timber in many different applications like exterior cladding, decking, flooring, garden furniture, panelling, kitchen furnishing and the interiors of bathrooms and saunas.
    Original languageEnglish
    Number of pages6
    Publication statusPublished - 2006
    MoE publication typeNot Eligible
    EventWood Protection 2006 - New Orleans, United States
    Duration: 21 Mar 200623 Mar 2006


    ConferenceWood Protection 2006
    Country/TerritoryUnited States
    CityNew Orleans


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