Selected Answers

From Cameron Duncan of M-NCPPC on May 4, 2016:
Efflorescence requires two things: moisture and bu ...read more Efflorescence requires two things: moisture and building material containing water-soluble salts. Solution 1: Eliminate either one permanently, and the issue is permanently eliminated (e.g., typical glass & steel construction). Solution 2: Assuming the latter (building material) is non-negotiable, maximizing the elimination of moisture requires preventing moisture from infiltrating the building material from above, below, outside face(s), and inside (e.g., bathrooms, condensation). Even then, high humidity environments can negatively affect building materials; man-made implies impermanent & imperfect; rising damp from salt-laden strata can infuse salts into masonry that effloresce; and air pollution deposits imbibed into building materials may subsequently effloresce. Solution 3: Build such that the efflorescent-prone material may be fully saturated long enough to salt-out (where all to most of the soluble salts have leached out). Conclusion: Solution 2 is most prevalent for most efflorescent-prone building today. "Permanent" is normally excluded from the man-made lexicon. Although imperfect and impermanent, an educated, protective plan/approach tends to best serve our needs.

From Brian Hall of Brichem Sales Ltd. on February 27, 2014:
Providing that you have solved the problems that m ...read more Providing that you have solved the problems that may be causing the moisture leakage, as Phil refers to, then clean the surface area and apply a coat of polysiloxane (available in clear or colored), let dry, and the problem is solved. Make sure that the polysiloxane has passed all ASTM requirements, including moisture vapor transmission, and can show excellent perm ratings.

From Philip Kabza of SpecGuy Specifications Consultants on February 24, 2014:
First - don't make any promises. And don't assume ...read more First - don't make any promises. And don't assume because one approach worked for awhile for someone on another project that the same solution will work for you. You must begin by analyzing and understanding the sources of moisture within the wall and how that moisture moves to the exterior. It is moisture movement that brings dissolved salts out of the mortar and deposits them on the surface of the brick. If moisture vapor drive is coming from high humidity areas inside the building, explore HVAC and interior vapor retarder solutions first. The classic example of this is the brick wall enclosing a swimming pool or locker room area. If moisture is entering the wall from the exterior, look at whether the mortar joints need re-pointing. If there are solid joints with good bond to the brick, and no visible points of excess water entry at the top of the wall, then turn to how you might dry the wall cavity (if any) by making sure the flashings and weeps are working, and introducing convection venting at the bottom and top of cavities. If that is not sufficient, very carefully consider a breathing, non-film-forming exterior water repellent. That latter is a last resort and not encouraged by the brick industry, but may be necessary in some circumstances.