Rain resistance of facades with facade details: A summary of three field and laboratory studies

Journal article, 2018

One of the main functions of the exterior walls and façade s to protect the indoor
and the sensitive parts of construction from the outdoor climate. Exposure of driving
rain is the most prominent moisture source a wall has to resist. Despite this, there is a
lack of information on rain resistance. Field measurements on real-life external walls
show that recurrent water leakage under driving rain conditions is observed in five out
of seven new-built houses in Sweden, including those with ventilated façade. About a
100 commercial laboratory tests, mounted by façade suppliers, and targeted laboratory
experiments showed that it is almost impossible to achieve fully tight façade solutions,
and keep them sealed. Nearly, all test walls with façade details leaked, almost regardless
of façade type and sealing efforts. The results from field and laboratory measurements
of rain resistance in new buildings in Sweden show that façade are usually not watertight
and also that very small deficiencies can cause substantial amount of water leakage.