White Efflorescence
White efflorescence is a water soluble salt that is brought to the surface of masonry by evaporation of either construction water or by evaporation of rain water that has penetrated the wall.
Water used in mortar, grout, etc. will sometimes cause this "New Building Bloom." As the wall dries out, and as successive rains wash the walls, the "Bloom" should disappear.
If the masonry has received its regular cleaning and white efflorescence appears or reappears, no further action should be taken until this wall has had an opportunity to dry out completely. Application of additional cleaning solutions may only aggravate the problem at this point. Also, application of clear waterproofing materials may lock in moisture and crystalline growth, causing more scumming and possible spalling of brick.
If efflorescence stains persist, it is likely that rainwater is penetrating the wall. An inspection of the stained areas should be made to determine if sizeable cracks or openings exist, permitting water penetration. Faulty flashing or a lack of flashing will contribute to staining.
Any large openings should be repaired. Where only very fine hairline cracks are assumed to be allowing water penetration, application of a penetrating water repellent may be the only solution to the problem short of a complete tuckpointing job.
Before applying waterproofing materials, all possible repairs should be made and all efflorescence removed. This may be removed by applying plain water and brushing the affected area. If water fails to remove stain, use dilute solution of commercial cleaning compounds such as Sure Klean 600, Diedrich 202 New Masonry Detergent (or equal) for red brick and Sure Klean Vanatrol, Diedrich 202V Vana-Stop (or equal) for all others. Some heavy white stains, known as "lime runs" or "silicone deposits" may require special cleaning procedures for removal. Contact the Brick Association of the Carolinas for further details. Allow entire wall to dry out completely (over a period of little or no rainfall) before applying waterproofing solutions.
Cleaning Masonry Laid with Colored Mortar
Colored mortar is highly sensitive to masonry cleaning solutions. While mineral oxide pigments are inert and are not affected by most cleaning materials, the materials will dissolve surrounding cement paste, allowing pigment to be washed away, exposing sand grains and causing a change in mortar color and texture.
Most manufacturers of colored mortar recommend cleaning with detergent and water only. Where mortar stains are heavy, a 1 to 6 solution of Sure Klean vanatrol, Diedrich 202V Vana-Stop (or equal) and water may be used; but a curing period of 3 to 5 weeks is recommended before cleaning with anything other than detergent and water.
Sandblast cleaning is usually acceptable, as is high pressure water cleaning with approved cleaning compounds. Protection of brick face must also be considered in selecting a cleaning system. (As with all cleaning jobs, test clean a sample area to determine effectiveness of cleaning compound and the total cleaning system and to check wall for possible damages caused by system. Approval of owner or owner's representative should be obtained before proceeding with operation.)
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