WISE is essentially a timber framed building and this main frame is constructed from glue laminated timber, plus standard timber beams for the roof.
Glulam is a type of glue laminated timber that is capable of spanning long distances.
Although glulam contains formaldehyde glue, this is only a very small amount and the finished product can be seen as much more sustainable than the alternatives of steel or concrete beams. The Glue Laminated Timber Association (GLTA) has claimed that the energy cost of a 305x165mm steel I-beam is six-times higher than a 550x165mm softwood glulam beam of equivalent strength. The case is similar for concrete beams, as a 400x250mm reinforced concrete beam would have five-times the energy cost of a comparable strength glulam beam.
Weight also becomes an issue with these other materials, as steel can be 20% heavier, and concrete 600% heavier, than equivalent strength glulam beams.
In WISE, glulam was used for the main structure, allowing us to have long stretches of frame without having to use steel or concrete. Some of the frame is on show, where it has an attractive finishing, but much is enclosed in the hemcrete (hemp, lime and 15% cement) which comprises the insulation and bulk of the walls.
|Timber Type||Embodied Energy (MJ/kg)|
|Glue laminated timber||12|
Timber Beam Roofing
The beams for the roof of WISE were constructed of FSC certified softwood timber. Glulam was not used for this as the lengths and strengths needed were not so great. As such, this timber has a slightly lower environmental impact than that found in the main frame. The insulation for the roof is cellulose (Warmcell)
All of the timber used in the construction of WISE comes from FSC certified forestry. The Forest Stewardship Council is an international NGO, founded in 1993, which promotes the responsible management of forests throughout the world.