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USG Levelrock® Brand 4500 floor underlayment is an engineered cementitious underlayment designed by USG for interior use in commercial, institutional and rehab construction. It provides a smooth, hard underlayment surface over concrete slabs, pre-stressed concrete and concrete planks at thicknesses from featheredge (with proper sand) to 2 in. Suitable for a variety of floor coverings, USG Levelrock® 4500 engineered cementitious underlayment exceeds commercial vinyl floor-covering requirements as a high-performance underlayment with compressive strengths of up to 5500 psi. Quick set times and high production rates allow for traffic within hours of installation. The exceptional surface hardness of USG Levelrock® 4500 floor underlayment resists indentation from trade traffic. USG Levelrock® 4500 floor underlayment features an innovative self-sealing technology that typically permits the floor covering to be installed without the need to seal the underlayment— minimizing installation cost and time. Once USG Levelrock® 4500 floor underlayment is dry, floor coverings of any type may be applied directly to the underlayment surface. USG Levelrock® Brand 4500 FR floor underlayment is an engineered cementitious underlayment designed by USG for interior use in commercial, institutional and rehab construction. Reinforced with fibers that improve impact strength, it provides a smooth, hard underlayment surface over concrete slabs, pre-stressed concrete and concrete planks at thicknesses from featheredge (with proper sand) to 2 in. Suitable for a variety of floor coverings, USG Levelrock® 4500 FR engineered cementitious underlayment exceeds commercial vinyl floor-covering requirements as a highperformance underlayment with compressive strengths of up to 5500 psi. Quick set times and high production rates allow for traffic within hours of installation. The exceptional surface hardness of USG Levelrock® 4500 FR floor underlayment resists indentation from trade traffic. USG Levelrock® 4500 FR floor underlayment features an innovative self-sealing technology that typically permits the floor covering to be installed without the need to seal the underlayment—minimizing installation cost and time. Once USG Levelrock® 4500 FR floor underlayment is dry, floor coverings of any type may be applied directly to the underlayment surface. USG Levelrock® Brand Floor Underlayment 4500 Pre-Sanded is a pre-sanded version of the 4500 product. It allows for ease in application at the jobsite. USG Levelrock® Brand Floor Underlayment 4500, 4500 FR and 4500 Pre-Sanded Self-Leveling Underlayment products may assist in obtaining LEED credits 5.1 and 5.2.