Study of a hempcrete wall exposed to outdoor climate: Effects of the coating

The results show that an important humidification of the wall can occur if the coating is not well chosen. The exterior coating must be very permeable to water vapour, but it seems to be important to prevent the absorption of rain as well, otherwise, the humidity inside the wall can lead to degradations such as mould growth or increased thermal conductivity. Both numerical simulation and measurements show that applying a vapour permeable coating on the blocks does not slow down the drying process, the hempcrete itself being the limiting factor.