MAPEI's Keracolor U grout is unsanded. So, it's a great choice for grouting most installations of glossy wall tile. Other good options are Ultracolor Plus FA grout and Ultracolor Plus Max grout. When grouting installations of antique or handmade wall tile, it is recommended to build a mockup (sample board) or, at the very least, test these products in an inconspicuous area before grouting.
MAPEI's Keracolor S Sanded Grout, Keracolor U Unsanded Grout, MAPEI Flexcolor CQ, Kerapoxy CQ, Ultracolor Plus FA and Ultracolor Plus Max grouts are all recommended for use outside in uncovered, exterior areas.
ASTM G21 is an industry standard that uses an intensive testing protocol for determining if fungi, including mold and mildew, can grow on a polymeric material. MAPEI uses a third-party lab and the ASTM G21 standard for testing the antifungal effectiveness of MAPEI products containing polymer that incorporate BioBlock technology. The ASTM G21 test uses a mix of mold and mildew spores that are commonly found in household environments. Product samples are placed on nutrient-containing plates and sprayed with a mixture of these fungi. For 28 days, the test plates are kept at a constant temperature of 84.2°F (29°C) and exposed to high humidity, which are excellent conditions for fungal growth. The samples are then examined for fungal growth. If no growth is present, the product is considered to not support mold/mildew/fungal growth.
For homeowners and building owners, the advantage is after installation. MAPEI’s BioBlock products will not support the growth of mold/mildew/fungi – with adequate cleaning and maintenance practices.
The advantage for contractors and installers is that MAPEI’s BioBlock products do not support the growth of mold/mildew/fungi – with adequate cleaning and maintenance. Therefore, their use can increase the life of an installation, resulting in fewer callbacks for installers and contractors.