Barnhart Specialty Contracting is an expertly-trained Licensed Applicator for Hacker Industries FIRM-FILL® gypsum concrete and cementitious floor underlayments and sound control mats. We proudly serve the state of Kansas, Kansas City, NW Missouri and SE Nebraska with floor levelers, underlayments and concrete toppings. Typical reasons for using Hacker FIRM-FILL® gypsum concretes and cementious underlayments include Fire-resistance, Radiant Heat Fill, Floor Leveling, and Sound Insulating.