Here at Inhabitat, we're all about new advancements when it comes to design. That's why we are so excited about an interesting technology coming from Scandinavia called ThermoWood, a sustainably harvested, extremely durable type of timber manufactured in Finland. Design studio też architekci chose ThermoWood as cladding material for their new residential project in Poland, prompting Treehugger's Lloyd Alter to take a closer look at the product, which combines benefits of both hardwoods and softwoods and offers an interesting alternative to the often hazardous chemically treated wood.
We’ve seen some great new developments in the field of sustainable cladding materials, like low maintenance softwood by Norwegian manufacturer Kebony and clever reclaimed Wabi Sabi. That’s great, because pressure treated wood often features hazardous chemicals that increase its durability but can be toxic when loose wood dust particles or fine toxic residues are generated. While some of these products have been pulled from shelves or replaced with those using alternative coatings, many among the currently used wood preservation technologies still present some risks to consumers. ThermoWood, on the other hand, uses only heat and steam and no chemicals at all.
According to the company’s website, the manufacturing process for Thermowood includes three phases of heat treatment, and improves the stability and biological durability of wood. It also improves its insulation properties, with high temperatures removing resin from the raw material. This technology can be applied to common softwoods like pine and spruce, ultimately reducing the need for chemically treated wood. The company’s analyses show that, despite using more energy for the heat treatment, the energy used in the making Thermowood is still pretty low. Oil-based stain products protect the wood and its unique walnut color against UV rays. Without any additional coating, the wood gets a grey patina that doesn’t affect its durability.
“Standard tests (EN 113, ENV 807) made in laboratory conditions have proven a significant improvement in biological durability. Improvements in biological durability are a result of the removal of natural food sources in the wood and also changes in the chemical and structural composition. Levels of resistance to fungal decay increase as higher temperatures are used.”
The Polish designers decided to use ThermoWood as exterior cladding material for their all-black house, taking advantage of its beautiful, finewood-style and excellent performance. The project, expected to be built near the village of Wojnowo in Poland, is a kind of bungalow that changes in height depending on the configuration of the site. It will comprise various spaces and environments, glimpses of which are provided through windows and a large glass surface that opens onto a terrace.