I have just laid a HUGE ceramic tiled kitchen floor and used BAL Flexible Floor Grout in Limestone (that't the colour it is called). It looks absolutely awful and doing a search I see another forum discussing the EXACT same problem means that this is not just a one off. The grout (supposedly a subtle beige tone colour) is patchy and in places totally white. I have emailed BAL today to ask for a resolution for this but any help would be much appreciated. I have cleaned it and washed it down and when wet it all looks a lovely mid brown even colour although then when dry the patchiness moves about I would say the floor is 85-90% mess grout wise. Would a sealant darken it to the 'wet' look colour?
This is deffo a case of efflorecence......it can be caused by excessive use of water when cleaning grout up...It is a salty residue caused from the Portland
cement in the substrate etc....and it rises to the surface causing this white residue....just use lithofin
cement away or similar and it should help.....
There are many causes of efflorecence but excess water is the main one...
following this info in future should help.....
How to Grout Properly
Why does grout discolor? 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. Follow these step-by-step tips and you will bring about beautiful, long-lasting and low-maintenance colored grout installations.
What is efflorescence?. Efflorescence is the movement of moisture upward through portland
cement beds and concrete slabs causing salts to rise to surface. Efflorescence causes grout discoloration.
Allow tile to set firmly before grouting. Grouting
tile too soon, before the setting material has set-up, can lead to many problems. Uncured setting material may bleed through the joints and discolor the grout. Also, there is the risk of destroying the bond by shifting tiles. Allow as much time between settng and grouting as feasible. read setting times on bags. These can vary with temperatures..
Job conditions must be controlled. When grout cures at different rates, shade variations will result. If various areas of an installation are exposed to heat (i.e., direct sunlight, or radiators) they will cure differently and unevenly.
How to properly mix grout. The amount of water used to mix the grout is of utmost importance. The right amount of water produces a firm, wet mix. An overly wet and soupy mix dilutes the grout, causing shade variations and poor strength (powdering). To ensure uniformity of color, a clean container and the same amount of water must be used in every batch. Throughly mix every batch. Let the material slake (stand) for ten minutes, then re-stir. Try to maintain the same amount of mixing time with every batch.
Application.
Prior to grouting, joints between tiles must be clean and free of excessive setting bed materials. Apply grout with a rubber float trowel, forcing it into joints to fill them completely. Remove excess grout with float.
Finishing. Wash the floor with a washboy or by hand sponge taking great care not to over wet the grout as this can take pigment out of the grout...and add to the chance efflorescence happening.