We have a lot of wood in North America that has to be chopped down now, thanks to the mountain pine beetle that is killing huge swathes of North American forests. It is a good reason to look at how we can substitute wood for steel and concrete in construction, to help use it up before it rots. CREE, (short for Creative Resource & Energy Efficiency) is an Austrian contractor that has developed an interesting hybrid prefabricated construction system that uses glue-laminated timber and concrete. They've built an eight storey building in Austria, LCT1, that demonstrates the system, and just in time for Greenbuild, they are bringing their system to America.
Glue-laminate timber, or Glulam, has been around for a while; it was first patented in Germany in 1872. In 1942 waterproof phenol-resorcinol adhesives were introduced and the use of the material became widespread. One of the biggest structures using was the Richmond Oval built for the 2010 Winter Olympics, covered in TreeHugger here.
The CREE system uses it as as a structural frame with concrete as the decking, and is described in more detail in a press release:
The wall facades are made from glue-laminate posts, while the floor slabs are constructed from a hybrid of glue-laminate posts and concrete. While these components are manufactured off-site, the foundation of a building is laid and the structural elevator shaft core is erected. This core, made out of either steel and concrete or wood, stiffens the building and provides a frame from which the walls and floors can hang. The slabs and posts are assembled by interconnecting the preset pins and holes of the components. With this skeleton structure, architects can design a wide variety of layouts and exterior skins, to create dramatic and sustainable buildings.
The prototype LCT1 building in Dornbirn, Austria, designed by Hermann Kaufmann, is built to Passivhaus standards, with triple glazed windows and a heat recovery ventilation system controlled by CO2 measurement (this is a tight building, it could build up in there). The exterior is made from recycled metal, the interior is exposed wood. It was built in eight days.
CREE claims that the technology " can generate up to 90% less carbon dioxide emissions compared to conventional steel/concrete construction." They have adapted it to meet local fire and seismic requirements.
We have a huge problem in our forests; if we don't chop the beetle infested wood down and use it, then it will rot in place, releasing all that CO2 that was absorbed in its growth. Building out of wood could use a lot of it up, sequestering that CO2 for the life of the building. CREE technology is a step in the right direction.
More at CREE (warning: loud splash page)