Water dissolves salts from mortar, brick, grout or soil, carries them to the surface and leaves them behind as it dries. Efflorescence itself is cosmetic, but it maps where water is traveling through the wall, which makes it a diagnostic clue for failed flashings, blocked weeps and leaking joints. When salts crystallize beneath the surface instead, they can cause spalling.
Look at the efflorescence fanning out under each window, those sill flashings have no end dams.
Washing efflorescence off without fixing the water source just brings it back after the next wet season.
Also heard as
- bloom
- salt bloom
Related terms
Spalling
Concrete, brick or stone breaking off in flakes or chunks at the surface.
Mortar droppings
Mortar that falls into a masonry cavity during laying and piles up on the flashing, blocking drainage.
End dam
An upturned end at the termination of a flashing that stops water from running off the end into the wall.
Water repellent
A clear penetrating treatment that makes masonry and concrete shed rain while still letting vapor out.