Kick-Out / Diverter Flashing

Kick-out flashing (also referred to as diverter flashing) is a roof flashing detail that is suggested to be installed above the ends of a gutter when it terminates against a side wall. The objective for diverter flashing is to ensure that water that runs off of the roof surface is diverted (hence, the name) into the gutter trough, preventing the water from running down the wall behind the gutter.

The Concern

Not installing diverter flashing can allow water to run down the wall behind the gutter. Because there is a sidewall transition at these areas, there are openings in the wall where water can find it’s way in behind the siding, which can (and often does) lead to damage of building materials (framing, insulation, siding, etc.). This could also induce unseen mold growth.


The International Residential Code requires kickout flashing at all sidewall flashing terminations.

R905.2.8.3 Sidewall flashing. Base flashing against a vertical sidewall shall be continuous or step flashing and shall be not less than 4 inches (102 mm) in height and 4 inches (102 mm) in width and shall direct water away from the vertical sidewall onto the roof or into the gutter.

Here is the link to a video provided by James H. Hardie Company, a well-known national siding company, that shows how kickout flashing is suggested to be installed in accordance with the installation standards for their siding products.