Finally, there is a solution to your rooftop duct system needs that is the right shape, the right material and the right price. We have combined our 40+ years of quality metal duct fabrication with a willingness to innovate and explore new technologies. The result is PhenoliDuct™. We combine the proven technology of our double-wall duct manufacturing with the properties of Kingspan KoolDuct® to give you the perfect rooftop ducting solution.