Thompson's Emergency Roof Repair Mastic has been developed to repair severe gaps and cracks to roofing substrates even under water. For ultimate adhesion start by remove any surface debris or fungal growth by scraping or vigourous stiff brushing.

Apply directly to the leaking area, wet or dry, with a trowell or pallet knife working well into the area to be repaired. The hydrophobic formula will displace moisture and adhere to the substrate for a water tight seal.