TSE CEN/TS 15679

TSE CEN/TS 15679 is the technical specification that defines thermally modified timber (TMT) and describes its characteristic properties. It focuses on the material category created when wood is heat-treated to alter its physical and structural behaviour, so the product can be identified, described and discussed in a consistent technical way.

TMT is usually a semi-finished timber product used in interior dry or humid conditions as well as in exterior exposure. Typical applications include flooring, panelling, cladding, decking, windows, doors, furniture and other internal or external joinery. In practice, the relevant characteristics of such timber are linked to how heat treatment changes moisture response, dimensional behaviour, appearance and service suitability.

Why the characteristic profile matters

From a general timber-technology perspective, thermal modification is used to influence the way wood interacts with moisture and to create a product with a distinct performance profile. That is why the distinction between definition and characteristics is important: the same wood species may behave differently depending on treatment intensity, intended use and exposure conditions. This specification also notes that where a product standard exists, its requirements and test methods should be taken into account; for load-bearing applications, reference should be made to the relevant EN standards.

In short, the document provides the technical vocabulary and property framework for TMT, helping distinguish it from untreated timber or other modified wood products. It is most useful when the timber is being selected, specified or compared for interior, exterior or joinery applications, especially where another product standard or structural standard also applies.