What is kickout flashing on a metal roof, and where is it needed?
Short answer. Kickout flashing is a small angled diverter at the bottom of a roof-to-wall intersection that kicks water out into the gutter instead of letting it run down behind the siding, and a metal roof needs one wherever a roof edge dies into a sidewall, just like a shingle roof. On metal roofs it is usually a formed piece that ties into the sidewall flashing and extends past the wall face over the gutter.
Why it matters
Water running down a sidewall flashing gathers speed and volume. At the bottom, if nothing turns it, it runs off the end of the flashing straight onto the wall, behind the siding, or into the joint between the gutter end and the wall. Over years that rots sheathing, framing and window frames below. The residential code calls for a diverter at this spot, and missing kickouts are a well-known cause of hidden wall rot.
Where it goes
- Wherever an eave runs into a sidewall, such as a porch roof meeting the house or a lower roof meeting a second-story wall.
- At the lower end of dormer side walls.
- Anywhere sidewall flashing ends above a wall instead of a gutter.
How it goes in on a metal roof
- The kickout is installed first at the bottom of the wall, over the eave trim and underlayment and under the housewrap.
- Sidewall flashing laps over the kickout from above, so water flows into it.
- The diverter extends past the wall face and out over the gutter.
- Housewrap and siding lap over the kickout's wall flange, with the siding held off the roof surface.
- Sealant is a backup at the joints, not the main seal.
Signs of a missing or failed kickout
- Stains or rot on the siding below the roof edge.
- Soft spots or bubbling paint on the wall or window trim below.
- Water stains inside on the wall beneath that intersection.