Lucas #4500 is a one component, non-shrink, advanced technology polyurethane sealant designed for the construction of liquid flashing systems and sealing roof penetrations, metal roof seams & fasteners, inlaid gutters, polyurethane foam, PVC and EPDM roofs. It may also be used on TPO roofs when primed with Lucas #8015. When used on smooth surface modified bitumen and asphalt BUR priming with Lucas #4015 2 Part Epoxy Primer is recommended. #4500 is compatible with Lucas water-based acrylic coatings. It is ideal for repairing hail damaged polyurethane foam roofs. Lucas #4500 is semi-self-leveling so that it can be used to perform general roof repairs, seal roof penetrations, gutters and metal roof seams & fasteners with minimal tooling. Viscous enough to avoid running on steep slope applications and drain out issues encountered with more liquid sealers. #4500 is 100% solids which results in zero shrinkage.