All living walls are irrigated via gravity. As such, the water goes straight down, and doesn’t touch the wall at all. However, for peace of mind and that rare occurrence where water does get on an interior wall, we recommend a waterproof layer be installed behind the living wall system. Some systems are designed to be watertight.
Exterior living walls generally do not need waterproofing between the system frame and the building, as it was already designed to withstand weather and the elements. As a preventative measure, we caulk or silicone the holes we drill into a wall to protect it from any water intrusion.