On the hygrothermal behaviour of brick veneer cladded timber frame walls: the role of the vapour diffusion resistance of the wind barrier

Syracuse, NY

The present study looks into the hygrothermal behaviour of timber frame walls with brick veneer cladding in a moderate sea climate. It specifically focuses on the contradictory criterion for the wind barrier when it comes to the risk of interstitial condensation for summer and winter conditions: a vapour open wind barrier is advantageous during an outward vapour flow (i.e. in typical winter conditions for European climates), while during an inward vapour flow (i.e. in summer conditions) a more vapour tight wind barrier is appropriate. Therefore, a field study is conducted on two typical timber frame walls with brick veneer cladding and wind barriers with different vapour diffusion resistance: the sd-value of the vapour open wind barrier and the more vapour tight wind barrier is 0.15 m and 1 m respectively at 70% relative humidity. The experimental results show little influence of the vapour tightness of the wind barrier: in general, relative humidity levels are similar in both walls. Outcomes of numerical HAM simulations indicate that this may be caused by the moisture buffer capacity of the different materials, which seems to play an important role to regulate the moisture levels inside the timber frame walls. Further research is needed, however, to draw general conclusions about the appropriate design of timber frame walls with brick veneer cladding.

https://surface.syr.edu/ibpc/2018/BE6/10