Todd Miller - Roofing Expert

#33 – Chimneys and Metal Roofing

One of the positive benefits of a properly installed metal roof is that it will be flashed in order to be watertight against roof penetrations such as chimneys, skylights, and dormers. Shorter term roofing systems are often just sealed in those areas, with the assumption that the sealant will last as long as the roofing material. A different approach must be taken with a long term metal roof though and that approach includes careful flashing against various penetrations and protrusions in the roof. Over the years, I have seen many cases where folks starting getting water infiltration around their chimney. They often assume the problem is the intersection of the chimney to the roof because, with other products, those sealants fail over time. With a properly flashed metal roof, though, rarely is the problem with the flashing. Usually the problem is due to deterioration of the masonry chimney or the chimney cap. One thing to look for is whether the leak is through the ceiling in the home or if the water seems to be traveling down or through the brick fireplace. If the water is showing up in the ceiling, it may very well be a flashing issue. If it’s tracking down the face of the fireplace, though, it likely is a masonry issue. As a safeguard, I always suggest having chimneys inspected and repaired prior to roof replacement.