Pipe boot leaks in asphalt shingles most often happen because the flexible rubber seal around the pipe has cracked, shrunk, or pulled away from the pipe or the shingles. This rubber flashing, called a pipe boot, is designed to create a waterproof seal where the pipe protrudes from the roof. Over time, exposure to sun, heat, cold, and weather cycles can cause the rubber to dry out and fail. Another cause can be poor installation, such as inadequate sealing or the boot not being properly nailed down under the shingles. Small tears or gaps in the boot allow water to seep beneath the shingles and into the roof decking, leading to leaks inside your home. You might notice water stains on interior ceilings or walls near the pipe or dampness in the attic space around the pipe.
For a safe DIY check, start by visually inspecting the pipe boot for cracks, splits, or gaps. Lift the surrounding shingles gently to make sure the boot is nailed in properly and flashing is intact. Look for rotted wood or damp insulation underneath if accessible. If you see any damage, you can apply roofing sealant around small cracks or edges as a temporary fix, but replacing the boot is usually the long-term solution. Because roofing work involves heights and sensitive materials, calling a professional is wise if you aren’t comfortable or if the leak persists after simple repairs. When hiring a roofer, ask if they will replace the entire pipe boot and how they ensure the new flashing will maintain a weather-tight seal. Also, inquire about warranties on the work and materials to ensure you’re protected down the road.