Where is head flashing typically installed?

Head flashing is typically installed on the upslope side of a roof penetration. This placement is crucial because it serves to direct water away from the penetration point, preventing leaks and water damage. By positioning the head flashing in this manner, any water running downhill will flow over the flashing rather than under it. This design ensures that the integrity of the roof system is maintained, as it acts as a barrier against infiltrating moisture.

In contrast, the other options represent areas where flashing would not effectively perform its function of directing water away from vulnerabilities in the roofing system. For instance, installations on the downslope side would not adequately shield the penetration from water flow, while placing it at the roof's edge or along the gutter line does not address the critical need to protect the upslope area directly. Hence, head flashing's essential role is to safeguard against leaks by ensuring effective water management at vulnerable points.