Around here, we have had 3 relatively warm and wet winters. Most masonry drying occurs during the windter months, when there are 10 - 15 days of single digit temps. This allows heat to flow out from the masonry, and the water in the masondy follows.
Because of this lack of drying time, we have a number of efflorescence teaching examples.
Three year old building. Brick veneer with cinder block structure. Notice how the efflorescence displays below the stone. No flashing under the stone cap. Water goes through the stone and vertical mortar joints.
Detail of proper single wythe CMU walls. Flashing must be in place above joist pockets with weep wicks. Above door and window lintals, similar flashing is needed with weep wicks. The lintal / brick space MUST NOT be grouted or caulked. It they are, this traps the water in the wall above the window and it leaks into the top of the window interior.
Notice how all the efflorescence is below the stone window sills and the stone parpet wall coping? Wonder why? Around here, mo one flashes properly. The result? Many buildings with water intrusion, mold and even rotting wooden floor trusses (the grout the joist pockets). Am involved with litigation inspections on 6 such buildings and 3 have already been torn down (rotted floor joists, mold) at the City’s order. But hey, it’s good money for me. Even have a new template for it, mostly boiler plate because the issues are almost always the same.
Lastly, got to see the spacing between the cinder block structural wall and the brick veneer. Where the efflorescence is, the required 1’ gap between the walls was filled with mortar. The “masons” (and I use the term loosely) didn’t bother to scrape the mortar off when laying the brick. Mortar bridges the gap between the walls. Any mositure going down the inside of the brick hits these bridges and seeps inward and outward. Moisture levels in the CMU, on the interior, was also elevated in these areas.
Put this together with themal imaging and mold sampling and you have a whole cottage industry for HIs.
Hope this helps;