Where should drip edge flashing be installed at the rake?

Drip edge flashing should be installed over the underlayment at the rake. This is critical because proper installation ensures that water runs off the roof and does not get underneath the roof covering, which could lead to leaks or water damage. By positioning the flashing over the underlayment, it provides a protective layer that directs water away from the roof's structure and into the gutters or drainage system.

This installation method helps to prevent water from seeping into the roofing materials and the underlying structures, which is essential for maintaining the longevity of the roof and preventing mold or decay. Additionally, having the flashing on top of the underlayment allows for moisture that may get under the roofing material to flow outward rather than being trapped, further protecting the structural integrity of the roof.

In contrast to the correct placement, installing drip edge flashing underneath the underlayment would not effectively divert water away from the roof edge, potentially leading to serious water intrusion issues. Similarly, options that suggest positioning the flashing above the roofing paper or along the edge of the eave would not provide the necessary protection and could compromise the effectiveness of the roof's drainage system.