I just came across this self-leveling underlayment from Custom Building Products.
“Formulated with CustomLite™ Technology, LevelLite is 40% lighter than other self-leveling underlayments, making it easier to carry and pour. Levels floors up to 2” thick in one pour. Seeks its own level in minutes. Rated extra-heavy for high impact use. Cures fast and develops high early and final strength for quick installations. Made with 100% recycled glass – contributes to LEED certification. Protected by MoldGard® Technology to resist mold and mildew growth.”
For more information, please visit their website by clicking here.