How to Grout Properly 1. Grout discolors because of poor installation tehniques, improper cleaning methods, efflorescence, and improperly cured setting beds. Color differences occur in different parts of an installation because the grout is allowed to cure at different rates. Uneven curing causes uneven color. Inconsistant mixing and installation techniques also cause uneven color.
Successful installations are the result of uniform, good installation techniques.
Checking for efflorescence. Efflorescence is the movement of moisture upward through portland cement beds and concrete slabs. Efflorescence causes grout discoloration. Make sure the tape seals all of the edges. If water condensation appears under the plastic within one or two days, efflorescence will most likely occur.