Sealing Critter Quitters to Roof

We have had some quesitons about sealing Critter Quitters to the roof after installation. This should not be done. Critter Quitters are designed for easy removal by plumbers if the vent needs to be snaked out due to pluggage. If the unit is glued or calked to the roof shingle damage could result when the unit is removed. As long as there is at least an inch of intact lead left around the base of the vent, a Critter Quitter should work fine.