ᐅ Installation level / wall construction

Created on: 22 Dec 2015 13:44
W
world-e
W
world-e
22 Dec 2015 13:44
Hello everyone,

I have a quote for a timber frame house with the following wall composition. KFW 55 is the minimum requirement, but the goal is KFW 40, if it is reasonably cost-effective.

However, I find the 8cm (3 inches) thick installation layer quite thick when considering the golden rule of 1/3 to 2/3.

From inside to outside:
Fermacell 12.5mm (0.5 inches)
Thermo hemp (installation layer) 80mm (3 inches)
OSB board 12mm (0.5 inches)
Mineral wool (thermal conductivity 0.035 W/mK) or timber studs 180mm (7 inches)
Wood fiber insulation board 0.044 W/m²K 60mm (2.5 inches)
Lime cement plaster 10mm (0.4 inches)

Looking at other wall constructions, it will probably require a 120mm (5 inches) wood fiber insulation board to reach KFW 40, assuming other corresponding measures are taken.

What are your opinions? Thank you very much.