Kickout Flashing

What Is Kickout Flashing

Kickout flashing, also called diverter flashing, is a specially shaped piece of metal installed at the bottom termination of a roof-to-wall intersection where a gutter is present. Its function is to catch the water flowing down the step flashing assembly and redirect it outward into the gutter, rather than allowing it to run off the last step piece and behind the wall cladding. A kickout flashing is typically a small, curved piece that extends 3 to 4 inches from the wall face and angles downward into the gutter trough. It is available as a pre-formed manufactured unit or can be fabricated from flat sheet metal on site. Despite its small size, kickout flashing prevents one of the most damaging and costly moisture problems in residential construction.

Why Kickout Flashing Is Required

The IRC now requires kickout flashing at roof-to-wall intersections where step flashing terminates above a gutter. Before this requirement was widely adopted, missing kickout flashing was one of the most common construction defects in residential homes. Without it, every rainstorm sends a concentrated stream of water behind the siding at the base of the wall. This water saturates the wall sheathing (typically OSB or plywood), which wicks moisture into the framing. Over months and years, this causes wood rot, mold growth, and structural compromise, all hidden behind the exterior cladding. By the time the damage becomes visible as staining or soft spots on interior walls, the repair bill can be substantial. A single kickout flashing piece prevents the entire problem.

Installation and Common Mistakes

Proper kickout flashing installation positions the piece at the very bottom of the step flashing run, integrated with the lowest step flashing piece and the first course of shingles. The lower edge of the kickout should extend over the back edge of the gutter so water drains directly into the trough. The wall-side leg extends up behind the siding like the rest of the step flashing. Common installation mistakes include angling the kickout too steeply so water overshoots the gutter, sealing the kickout against the wall so water has nowhere to drain, and using a site-bent piece that lacks sufficient curve to redirect the water effectively. Pre-formed manufactured kickout units are recommended because their geometry is engineered for optimal water diversion. When retrofitting kickout flashing onto an existing roof, the bottom few shingle courses at the wall must be lifted, the kickout positioned and secured, and the shingles re-laid.

Kickout Flashing in Insurance and Inspection

Missing kickout flashing is one of the most frequently cited defects in home inspections and one of the most expensive to remediate once damage has occurred. When an insured storm loss results in a full roof replacement, kickout flashing must be added at every applicable location as a code-upgrade item, even if it was not present before the storm. Adjusters should inspect the base of every roof-to-wall termination and document whether kickout flashing is present. If concealed wall damage is discovered during the roof replacement, the contractor may need to submit a supplement for siding removal, sheathing replacement, and mold remediation. Estimators should include kickout flashing as a separate Xactimate line item at each roof-to-wall location. Pre-formed kickout diverters are a standard material cost that should not be overlooked in the initial scope.