According to
the maker's of FlexBond® Premium Flexible Bonding Mortar, it:
"Protects against problems from minor surface movement"
"Provides the highest bond strength, exceeds industry standards"
"Is technologically advanced flexible mortar"
"Is the best choice for difficult tile installations"
Product Description
"FlexBond® Premium Flexible Bonding Mortar's technologically advanced formula provides maximum flexibility and bond strength. Twice as strong as industry standards. Protects against cracking from minor surface movement. Our cross-linked, cFlex3™ tri-polymer technology ensures enhanced flexibility, smooth, easy troweling and consistent, long-lasting results. Just add water and mix; no additives required."
This information is from Custom Building Products website, they are the manufacturers of FlexBond®.