February 24 - February 28, 2014
How do I get permanently get rid of efflorescence on clay brick?
Brian Hall of Brichem Sales Ltd. on
February 27, 2014:
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.
Phil Kabza of SpecGuy on
February 24, 2014:
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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.
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