Same with brick and stone facades. If you have a sprinkler system where water gets directed onto the building (intentionally or not), there's a phenomenon calle

Same with brick and stone facades. If you have a sprinkler system where water gets directed onto the building (intentionally or not), there's a phenomenon called "Vapor Drive" which is essentially capillary action. Without the air gap between the facade material and the wood framing, that moisture goes in there and rots the wood. http://mattrisinger.com/understanding-vapor-drive-in-reservoir-claddings-stone-brick/ http://mattrisinger.com/understanding-vapor-drive-in-reservo...