Would you want to live in a house that is all grey wood? Doesn’t sound very attractive does it? But what if we told you it is made of the most sustainable product in the building industry yet? Ah – that got your attention didn’t it?
We’re talking about a product that is currently made in Finland called Thermowood. It is made from sustain-ably harvested timber and goes through a 3 stage process of heat treatment which eliminates any need for chemicals.
The heat treatment used on this revolutionary is what makes the hardwoods and softwoods dimensional stable as well as durable biologically. Heat and steam are both used in the first step of the treatment, which raises the kiln temperature to one-hundred-thirty Celsius while the moisture content is reduced to almost zero.
Then the second step to create Thermowood is what is called “thermal modification phase” where the temperature is increased to 185 to 215°C and kept there for two to three hours. The third and final step phase is the cooling & conditioning which involves lowering the temp of the kiln by spraying water. After the temp is down between 80 and 90°C, the wood is re-moisturized to a level of 4 to 7 percent.
The thermal conductivity is reduced with this treatment process which improves the wood’s insulation properties. All the resin is removed from the high temperature that was used during treatment.
Now this may seem like the amount of energy used for making Thermowood is a lot, but the manufacture claims there isn’t. This process is said to work on all types of wood like pine or spruce, both of which are readily available.
Thermowood has been tested in labs that prove the wood is an improved biological durability when compared to wood that is chemically treated. The durability is made possible because the natural food sources of the wood are removed which changes its composition. The high heat treatment makes Thermowood fungus resistant too.
One drawback that designers may not care for when using ThermoWood, it comes only in a “walnut color” that has a unique dark tint. The color is homogenous all the way across each board and when treated with oil based stain, it protects it from the UV rays of the sun. If left untreated, the walnut color turns to a charcoal grey over a period of time.
From a sustainability point-of-view, Thermowood shows to be the green choice for those who are looking for an eco-friendly material to build their next home.