Premixed tile products are often marketed to the do-it-yourselfer
as a no mess, no hassle alternative to conventional cementitous tile mortars. Over the
years, a large number of complaints connected to the use of these types of products have
been brought to our attention, prompting us to publish the following information:
Premixed grouts have extended drying times and may not harden for days or even weeks
after the tile installation is complete. This is because premixed products rely on both
evaporation and the tile and substrate to wick or pull the moisture from the product
allowing it to slowly harden. Cementitious grout
mortar will harden within 24 hours and fully cure within 30 days. Cement hardens
through a chemical reaction (hydration) that bonds water molecules to the cement mixture.
We advise consumers to avoid using premixed grout products altogether.
Premixed thinset is not a true thinset mortar but an
organic adhesive mixed with an aggregate (sand) which is added to resist compressive stress.
Premixed thinsets may be used in place of mastic for non-vitreous ceramic tile installed in
dry areas not subjected to foot traffic but should never be used to install floor tile,
stone, semi-vitreous, vitreous, or impervious tiles (e.g. porcelain or glass tile).
Cementitous grout and thinset mortars do require more effort to mix, however, cement
has proven itself both reliable and durable over a period of thousands of years. Cementitous
grout and thinset mortars are also much less expensive than premixed adhesives and grouts.