#MAPEITechTip: What is efflorescence and how can you reduce the risk of its occurrence?

Efflorescence typically occurs when soluble salts (minerals) from the Portland-Cement are carried to the grout surface by excess water. As this water evaporates—it dries as a chaulky white haze on both the grout joint and tile surface. These minerals can rise to the surface either from the Portland-based cement in the substrate or grout and/or a combination of both—causing efflorescence. Here are a few tips to reduce the risks:

Grouting Process: During the mixing, only use the amount of water recommended by the manufacturer.  Introducing additional ‘water of convenience’ runs the risk of providing the means for efflorescence to occur.  Also, during the cleaning process, ring the sponge out wet/dry, and avoid over scrubbing the grout joints.  Not only will this lessen the risk of efflorescence, but it will also ensure that you are not scrubbing out the colored pigments in the grout. For additional information on efflorescence, visit the Tile Council of North America (TCNA) website.

Encapsulate the cement-based substrate:  with a liquid-rubber waterproofing, separating it from the rest of the installation system, interrupting the rising damp mechanism from the slab. Apart from controlling the amount of water introduced, separating the Portland-based render coat or concrete substrate from the rest of the installation system, using a liquid-rubber waterproofing, such as Mapelastic AquaDefense can aid in reducing the risk of efflorescence.  Once the waterproofing layer is applied use a mortar and grout that does not contribute to efflorescence as part of the layering system.  How is this achieved?—cementitious mortars that use calcium aluminates (hydraulic cements) in the formula are not susceptible to efflorescence like MAPEI’s Granirapid System or Ultraflex LFT Rapid  This same technology is also formulated into MAPEI's ANSI A118.7 cementitous grout, Ultracolor Plus FA to provide a complete system—minimizing the risk of efflorescence.

For a truly efflorescence free solution to your commercial and residential grout project…try MAPEI’s acrylic-based ready-to-use grout Flexcolor CQ.  Formulated with quartz aggregate, which ensures color consistency, stain & chemcial resistant, ease of cleanability and improved workability.