What Is Kickout Flashing and Why Does It Matter?
South Jersey Construction Consultants Inc. — reviewed October 2026
Kickout flashing is a small bent piece of metal that sits where a roof edge meets a wall and kicks rainwater out into the gutter instead of letting it run behind your siding. That’s the whole job — and it matters more than almost anything else on your exterior. When it’s missing, every rainstorm funnels roof water straight into your wall, rotting the sheathing (the wood panels under the siding) for years before you see a stain. It’s a small part with big consequences, and it’s one of the first things we check on homes across South Jersey.
How does water get behind siding at a roof line?
Picture where a lower roof dies into the side of your house — common over garages and additions in Cherry Hill, Marlton and Mount Laurel split-levels. Shingles meet the wall in steps, with an L-shaped piece of metal called step flashing under each shingle course. Step flashing moves water down the wall safely — until the last step. Without a kickout at that bottom step, the stream hugs the wall and runs straight behind the siding.
Diagram is a visualization, not a photo of a specific house.
What does a missing kickout do to a wall?
The damage is slow and hidden. Water soaks the sheathing, then the bottom plate and studs (the wall’s framing), and sometimes the rim joist (the beam the floor sits on). From outside you might see a brown streak below the roof line or staining at the corner of the gutter. Inside, the first clue is often a soft spot in drywall or a musty smell. On tear-offs, the worst rot we photograph is almost always below a roof-wall intersection that never had a kickout.
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The flashing chapter includes a kickout diagram and the exact scope lines to demand in any siding quote.
Text Me the Free GuideHow do you know if your house has kickouts?
From the ground, find every spot where a roof slope ends against a wall above a gutter. Look for a small angled metal piece sticking out over the gutter at that corner. If the metal just runs flat into the wall and disappears, there’s no kickout. Gutters that overflow at one corner every storm are another hint. Kickouts work together with your gutters and downspouts — the kickout delivers the water, the gutter has to carry it away.
Can kickout flashing be added to an existing house?
Yes. On a finished wall we open a small section of siding, install the kickout integrated with the wall’s water barrier, and close it back up. During a full re-siding it’s simple — the wall is already open, so we install and photograph every kickout before the new siding covers it. Either way, get it listed as a written line item. “We always do that” without a scope line means you can’t verify it happened. Watch one go in on our videos page.
Frequently asked questions
Is kickout flashing required by code?
The model building code has called for flashing that diverts water away from the wall at roof-wall intersections for many years, and inspectors commonly look for kickouts. What applies to your house depends on the code edition your town has adopted VERIFY: NJ-adopted IRC / local enforcing agency.
How much does it cost to add a kickout?
The part is cheap; labor depends on whether siding and roofing must be opened to reach the spot. During a re-siding it’s a minor line item VERIFY: SJCC price book, current rev.
Is kickout flashing included in a siding replacement?
On our jobs, yes — every roof-to-wall termination that drains toward a gutter gets one, photographed before it’s covered. Ask any contractor to put kickouts in writing.