Total - Energies

For the parquet floor, there’s ash that’s as hard as ebony. For the window frames, poplar instead of oak. These non-standard woods, tougher and more resistant to moisture, insect attack, decay, biodegradation and wear, are obtained as a result of a new heat treatment known as “retification®” (from the French words réticulation and torréfaction). This technique, discovered in 1984 by Professor René Guyonnet, a researcher at France’s École des Mines in St-Étienne, involves “cooking” the wood for several hours, at temperatures ranging from 200 °C to 290 °C depending on the type of wood, to make it water-resistant and totally indigestible by parasites. Retification® is an environment-friendly process which replaces the usual chemical treatments based on copper salts, chromium and arsenic, which are particularly harmful to the environment. Above all, retified® woods do not swell and shrink with changes in the ambient humidity, so they are easier to work. They also have an attractive light caramel color, give off a very slight odor of roasted coffee and are extremely light. On the other hand, the potential applications of retified® wood could well revolutionize the use of wood in a number of areas. And its good resistance to the effects of weather and time could well end up relieving the pressure on the world’s forests. At present, retified® wood seems to be mainly used outside (garden furniture and cladding for facades), but other uses are likely to follow. So far, the cost of this heat treatment limits retified® woods to up-market uses, but strong international competition is bound to bring costs down to consumer level.