Double web girders, also known as parallel trusses or web girders, are profiled wooden girders. They consist of an upper and a lower chord, which are connected by a central bar. The belts are made of solid wood or glued laminated veneer lumber, the bridge is made of wood fibre or OSB boards. This creates a rigid beam that is still very light with a high load-bearing capacity. Due to the lower proportion of wood in the cross-section, a larger proportion of insulation is possible in the building element, which is why the web girder is also particularly suitable for highly insulated roofs (e.g. in passive houses).
Source: bauwion
