Have you ever noticed this cloudy deposit on brick walls before? It’s called efflorescence. This is the salt and other dissolved material that is left behind when water evaporates. But how does it get on brick walls?
On a newly built brick wall it can come from the water in the mortar evaporating. It’s common to see efflorescence on newer brick walls for a short while after they are built. It's a temporary issue.
On walls that have been around for years, it’s a sign that one of two things are happening. The first is that water is hitting the surface of the wall from the outside. This could be from a faulty eavestrough or downspout sending water to the surface of the wall. The other potential cause is a significant source of moisture inside which is working it’s way through to the outside of the wall. When efflorescence is noted, it’s important to understand the cause and take corrective action against the troublemaking water.