Borrowed from French efflorescence, from Latin efflorescere, which was from ex- (“out”) + florescere (“to blossom”). It's called "efflorescence,"
and it's a crystalline deposit of salts often seen on the surface of concrete, brick, stucco or natural stone surfaces. It occurs when water leaves behind salt deposits and is present on or in the masonry surface. It traverses to the surface of brick walls including plastered walls.
This is a significant problem especially in Coastal Areas, although moisture in the walls could also be a problem.
The salt condition should gradually decrease in two to three years, but will remain constant in wet walls. It is imperative that proper waterproofing be done to get the moisture out of the walls as the problem is from the inside out.
A. Existing Walls:
- All visible salt vesicles must be broken open;
- A firm nylon brush should be used;
- It is important to place a plastic cover on the ground to collect the salt deposit, salt deposits falling on the ground are absorbed into the soil with rain or water and just return to the wall;
- No water should be used to wash out the vesicles - it makes a solution and spreads again in the wall;
- No high pressure device should be used - see 4.
- Walls should be well sanded;
- Cracks larger than 3mm must be opened and plastered - smaller cracks can be Skimmed;
- Walls should be washed with sugar soap;
- Hair cracks need only be covered with "Classiseal Primer". After preparing the entire wall as in 1-8, a second layer "Classiseal Primer" must be used before applying two to three layers of "Classic Satin Sheen" or "Classic Super Acrylic".
- It is always better to apply three thin coats than two thicker coats.
B. Newly plastered walls
- One layer of "Classiseal Primer" must be applied;
- Walls can be skimmed with a good quality Skim Plaster;
- When desired finish is obtained, one layer of "Classiseal Primer" must be applied to the Skimmed Plaster;
- Now two to three layers of "Classic Satin Sheen" or "Super Acrylic" can be applied.
C. Walls on top
All walls on top should be sealed with a cementitious water proofing and painted as recommended in A. and B.