Treadstone® FR30P's proprietary formulation provides an efficient, effective solution to projects requiring pre-pours of underlayment between interior walls, and below locations of tubs, shower enclosures and other areas containing appliances installed before the installation of underlayments. Requiring no sand, FR30P gels quickly after pouring, and the slower flow and increased viscosity provide additional protection from potential leaks. FR30P maintains the fire resistive non-shrinking, fast cure properties associated with gypsum underlayments.