Prefabricated timber walls: load-bearing, insulated, factory-made
Prefabricated timber walls are manufactured in the factory and only assembled on site. CL-THERM, the wall system of BOI Bau Orkestra, combines structure and thermal insulation in a single element.
- Wall thickness
- 160–320 mm
- U-value W/(m²·K)
- down to 0.12
- Element width
- ≤ 16 m
- European approval
- ETA-25/1030
What are prefabricated timber walls?
Prefabricated timber walls are timber wall elements that are not built brick by brick on site but manufactured industrially in advance. Window and door openings, recesses and connections are prepared in the factory. On site the elements are simply set in place and connected.
CL-THERM goes one step further than many prefab walls: the wall is not just an enclosure but load-bearing and bracing – and the insulation is already part of the wall section.
Build-up of a CL-THERM prefabricated timber wall
Each element is a glued ribbed panel. According to the technical data sheet (ETA-25/1030) it consists of:
- SWP cover layers inside and outside – single-layer solid wood panels, 20–40 mm
- Layers of solid timber ribs (spruce/fir, strength class C24), alternating horizontal and vertical, 40 mm each
- Lignatherm wood-fibre insulation (WF to EN 13171) between the ribs
- Bonded with PUR adhesive type I to EN 15425
Advantages over masonry and reinforced concrete
Because the walls are made in the factory, construction time on site is much shorter and largely independent of the weather. Dimensional accuracy is high: thickness tolerance ±2 mm, width and length ±3 mm.
The integrated wood-fibre insulation achieves a U-value of 0.366 to 0.168 W/(m²·K) depending on thickness – without an additional external insulation system. With additional external wood-fibre insulation the wall build-up even reaches 0.12 W/(m²·K). Wood fibre also stores a lot of heat (c = 2,100 J/(kg·K)) and is vapour-open (μ = 3), which stabilises the indoor climate in summer and winter.
Dimensions and applications
CL-THERM is produced in wall thicknesses of 160, 200, 240, 280 and 320 mm; the number of layers increases with thickness. One element can be up to 16 m wide and about 3.45 m high.
The system is used for detached houses and villas, apartment buildings, offices and commercial buildings, schools and public buildings, and rooftop extensions – in service classes 1 and 2 to EN 1995-1-1.
From the plan to the finished wall
The starting point is the architect’s plan. From it, the shop drawings for every single wall element including all openings are prepared. After production the elements are delivered and installed. BOI Bau Orkestra supports developers, architects and investors in Türkiye through this process – from the first enquiry to delivery.