All roofs have venting penetration points that are designed to help either ventilate harmful gases outside the structure from gas fueled appliances within the home, or for ventilating air out from the attic space to maintain an ambient temperature within the attic space, or also for allowing outside air to be pulled in for mechanicals that need combustible air from the exterior for proper operation.
In all cases each have one thing in common. They penetrate the roof covering at their respective location. Having a scheduled annual Roof Inspection will allow for a home owner to properly evaluate the current condition of their penetration points. A penetration point should have a boot at it's base that is properly installed with whatever roof covering overlapping the boot. There should also be roofers tar generously applied over the roof covering that is directly covering the boot base creating an optimal seal to prevent water from intruding into the interior at the penetration point.
Over time and through the seasons the roofers tar can become weak, brittle and start to crack. When this happens it allows for an entry point for moisture to intrude that can be the start of a gradual problem that could increase into a large problem if not addressed. It is recommended my most home inspectors during a home inspection that the penetration points should be reinforced at the base of the point with some roofing tar as a proper annual homeowners preventative maintenance plan.
Home Inspector Albuquerque 505-333-4041 8201 Golf Course Rd. NW, Suite D-3 #181 Albuquerque, NM 87120