Thompson's Emergency Roof Seal immediately fills and bridges small gaps and holes, even in heavy rain. It flexes with the natural movement of the roof for a tough, long lasting, watertight repair. This sealant is waterproof and can be applied during a downpour, drying immediately for on-the-spot repairs. It is most suitable for filling smaller and shallow cracks and is black in colour. Clean up tools and spills using white spirit.