Some common complaints about Flex Shot include the pressure in the Flex Shot can running out before the product is out of the can, the seal not working correctly, and the can not being easy to use. Some people also complain that the product is overpriced for its value.
Most customers on Amazon.com complain that Flex Shot does not work as effectively as its advertisement promises. One reviewer complains that he used the product to seal his leaking roof, but it still leaks after using three cans around seven screws. The reviewer says that he has used it on small seepage leaks, but it does not seal at all. Another consumer complains that he cannot use his Flex Shot because he does not understand how to use the can.