The roof inspection is one of the most important part of the home inspection. Home inspectors spent a lot of time examining the roof covering as well as the flashing installed around the roof penetrations. Vent stacks is an area that must be properly flashed in order to keep rain water from making its way to the interior. Tar is often used in place of flashing to seal gaps, however this is only a short quick fix. Metal flashing in most cases is used and is most effective. But in order for it to be effective it must be installed properly.

According to industry standards, a flashing must be provided where a plumbing stack, mast or flue protrudes through a roofing system. The flashings are usually  constructed of metal or rubber. The flashing slides under the shingle material on the sides and uphill portion of the vent. On the downhill side, the flashing is exposed, overlapping the roofing material. This will allow rain water to flow away from the roof vent and into the gutters.

The pictures above shows the roof shingles installed over the roof flashing, and a heavy amount of tar put on the vent stack and shingles. This is a potential leak area because tar is not an effective means of flashing.