Chimneys, vents, and caps: the roof items nobody walks

Roof walks tend to stop at shingles and ponding — but the envelope fails at the penetrations. A missing vent cap lets water and pests straight in, a cracked chimney crown channels water into the masonry, and a displaced flue cap can affect the appliance below. None of these show from the ground, and all of them show up later as ceiling stains that look like roof leaks in the wrong place. Add a penetrations pass to every roof walk: every vent, cap, and chimney, photographed, in order around the roof. Which penetration has caused your worst mystery leak? — Admin