FIRMFILL Gypsum Concrete floor underlayments | | Hacker ...
FIRMFILL ® Gypsum Concrete . The original FIRMFILL® Gypsum Concrete floor underlayment is designed for use in multifamily housing to satisfy acoustical ratings and fire codes. With excellent STC and IIC ratings as well as over 105 UL listings, FIRMFILL® Gypsum Concrete floor underlayment is an excellent choice for jobs needing ...