When dealing with efflorescence, there are a few simple rules to remember.
- use sill pans in all openings;
- use slumps in the 100-mm (4-in.) range;
- use low-alkali portland cement;
- provide overhangs at roofline and sills;
- use vapor retarder under slabs and in walls;
- use durable, preformed end-dams at openings;
- keep water-cementitious material (w/cm) ratio low (approaching 0.45);
- use waterproof liners in planters and fountains;
- waterproof below-grade spaces, including elevator pits;
- use proper drainable weeps spaced maximum 610 mm (24 in.) on center (oc);
- install a moisture barrier between coping and masonry;
- use durable through-wall flashing turned up the back and sealed;
- substitute portland cement with recommended proportions of fly ash; and
- specify brick with additives that neutralize alkaline sulfates or are free of such.
- use wet curing methods;
- use clean potable water free of salts;
- keep sprinkler systems off walls;
- cover brick cubes until ready for use;
- provide drainage away from structure;
- use aggregate washed in potable water;
- follow American Concrete Institute (ACI) 306, Guide to Cold-weather Concreting, for applicable conditions;
- do not clean masonry with pressure-cleaning;
- consolidate grout pours with a mechanical vibrator;
- cover the tops of unfinished masonry walls and sills;
- do not pour grout or concrete in cold or damp weather;
- do not use sea sand or aggregate washed in salt water;
- perform efflorescence testing on brick units before having them laid;
- tool mortar joints to a smooth, dense, and concave surface; and
- use clean fine and coarse aggregate washed with potable water.
For more on efflorescence, see article by Joseph “Cris” Crissinger called “Why red brick turns white: Understanding efflorescence.”
Joseph “Cris” Crissinger, CSI, CCS, CCCA, ASQ, has almost 30 years of experience preparing construction specifications. As director of corporate specifications with McMillan Pazdan Smith Architecture (Spartanburg, South Carolina), he is responsible for evaluating new products, maintaining corporate masters, preparing project specifications, assisting in facility assessments, performing field investigations, and coordinating internal training programs. Crissinger is a member of Construction Specifications Institute (CSI), along with the Building Performance Committee of ASTM International, and the Design and Construction Division of the American Society for Quality (ASQ). He can be contacted via e-mail at email@example.com.