2.2.1 Timber stud wall with sheet cladding

Double-stud wall structure significantly decreases the formation of thermal bridges and enables to diminish the weight of the entire structure. Thermal insulation layer is installed inside the double stud without an additional frame. The insulation layer thickness may vary depending on the required heat transfer factor U value. Thermal insulation made of PAROC WAS 25t sheets simultaneously serves as a wind barrier. This layer is fixed onto the studs. It is one of the best structures for a passive house (Figure 1a). An auxiliary frame on the internal side is required to install a tight vapour insulation, which in this system also serves as an air barrier. The vapour insulation is installed between the auxiliary internal frame and the thermal insulation layer in the middle. For this reason the engineering systems installed in the wall structure will not damage the tightness of the insulation layer. Four hundred and twenty millimetres of thick thermal insulation layer enables to achieve the U value ≤ 0.09 W/(m<sup>2</sup> K) [12].

Figure 1.

Structural solutions for walls: (a) timber stud wall with sheet cladding, (b) glued laminated timber I-joist stud wall with brick finishing and (c) plastered silicate block wall.

### 2.2.2 Glued laminated timber I-joist stud wall with brick finishing

Glued laminated timber (glulam) I-beam frame significantly reduces the impact of thermal bridges on the structure compared to the ordinary stud wall (Figure 1b). Thermal insulation made of PAROC WAS 25t sheets simultaneously serves as a wind barrier. This layer is fixed onto the studs. U value is ≤ 0.09 W/(m<sup>2</sup> K) when the thickness of thermal insulation layer is 420 mm [12].
