When conducting home inspections there are certain defects that a commonly found at the majority of houses. This is especially true with roofing. Minor roofing defects may include: fasteners that are no sealed, cracked or damaged sewer vent flashing, and shingles that do not lay flat.
Exposed roof fasteners should be sealed with roofing sealant or silicone caulk. If not sealed the fasteners rust and begin to loosen and/or back out of the roof. This can allow moisture to seep in around the fastener and wick into the roof decking or drip into the attic. Overtime even small amounts of moisture penetration can lead to damage to the roof decking or ceiling.
There are two main types of sewer vent flashing used in this area. The auto caulk boot, or the lead boot. The auto caulk boot seals around the vent pipe with rubber. Over time sunlight causes the rubber to become brittle and crack and, if not replaced, the rubber will completely deteriorate and leave large gaps around the vent pipe. The lead boot does not deteriorate by sunlight, but is susceptible to damage from rodents gnawing on the lead. Lead is a soft metal and ideal for rodents looking to sharpen their teeth. The damage often leaves gaps around the pipe that can allow moisture penetration.
Composition asphalt roofing shingles have adhesive on the upper top portion that adheres the shingles overlapping. This helps prevent wind uplift. If the shingles do not lay flat, they do not properly adhere to each other. This often occurs when roof fasteners are not driven properly and hold up the shingle above. In addition if the shingle is not laid properly is can buckle up and not lay flat.