What is Thermally Modified Wood?

The Thermal Modification process is a method where wood fiber is 'cooked' in extremely high temperatures for up to 60 hours. This will bring the moisture content down to 0 - 1%. During the last 30 hours, the temperature is gradually decreased while water steam is released into the kiln. This will increase the moisture content of the material back to 4-6%. In the Thermal Modification process the hemicellulose (sugar chains) are completely broken and the wood no longer contains sufficient nutrients to support fungi which cause decay. The process also permanently reduces the equilibrium moisture content down to about half of untreated wood. This means that TMW does not react to humidity changes as drastically as untreated wood, making it dimensionally more stable (than untreated wood). Originally invented in Europe during 1990's, TMW is increasingly replacing pressure treated wood, as well as tropical hardwoods in applications like decking, siding and even outdoor furniture. TMW is a 100% chemical free process.