Nine homes in ten in Kinnelon are detached houses, and Washington Township is close behind. A detached roof often has valleys, dormers or a skylight, and each one is a joint where two surfaces meet. Joints are where water finds its way in.
In winter the edge of the roof is the other suspect. Snow stays on Highlands roofs longer, and melt water can freeze at the cold overhang and back up under the shingles. The stain then shows up near an outside wall, often some distance from the actual opening.
In Lincoln Park, 22 percent of homes are attached houses, and in Montville 18 percent. A leak at the seam between two units can start on either side of it, so we look at both roofs where we are allowed to.
A ceiling stain only says water got in somewhere. We go up, follow it back, and photograph the opening before any repair gets a price.