weber jointseal PU is reliable low modulus polyurethane based elastomeric sealant, allowing a high degree of elongation. It cures under the effect of atmospheric humidity to form a flexible and resistant joint with very good adhesion on most materials. After stretching, it recovers its performances and its resistance to climatic ageing, rain, snow, salt haze, ozone, ultra violet rays and atmospheric corrosion. It can be later painted after full curing: a preliminary test is recommended. The weber jointseal PU sealant conforms to the requirements of ASTM C 920, “Standard Specification for Elastomeric Joint Sealants”, Type S, Grade NS, Class 25, Use NT and M.