Schluter® PRIMER-U Universal Primer cleaner Liquid-applied membranes (like RedGard) require

Liquid-applied membranes (like RedGard) require multiple coats

Not only does it cost significantly less than porcelain

Pro Tip: Clean the floor thoroughly before using a refresher

same waterproof KERDI construction

Schluter® PRIMER-U Universal Primer cleaner Liquid-applied membranes (like RedGard) requirePRIMER U is Schluter's universal primer a ready to use, water based formula that improves the bond of thin set mortar to substrates that resist adhesion. Where PRIMER PS is specifically for peel and stick membranes, PRIMER U works with standard mortar set Schluter products (DITRA, KERDI, KERDI BOARD) and general tile installation. Use it when your substrate is too smooth, too dense, or has residual contamination that would compromise mortar adhesion.