Chimney Rx Trowelable Chimney Crown Repair is an elastomeric coating that forms a flexible waterproof membrane over the surface of the crown. It is specifically formulated to repair and protect chimney crowns from water intrusion. It can also be used for a variety of horizontal and vertical exterior waterproofing applications. It dries to a natural concrete/mortar appearance. Chimney Rx Trowelable Chimney Crown Repair is an extremely long lasting and durable coating that requires no mixing or special bonding agents. Remember, shipping is FREE (continental US only).