What is Kick-Out Flashing?
Kick-out flashing is a small angled piece of metal flashing installed at the bottom of a step-flashing series wherever a sloped roof eave terminates next to a vertical wall above a gutter. Its job is to “kick” water out from behind the wall and into the open end of the gutter, instead of letting it run down the face of the wall behind the siding. Kick-out flashing is required by the International Residential Code on all asphalt shingle roofs at these junctions and is the single most common cause of hidden water damage when missing.
The corner where a sloped roof eave terminates next to a sidewall above a gutter. The cyan angled piece is the kick-out flashing, diverting water away from the wall and into the open end of the gutter.
What is the purpose of kick-out flashing?
Picture the bottom of a step-flashing series at a sidewall: the last piece of step flashing sits just above the gutter. Without something to divert the water, runoff coming down the roof slope hits the bottom of the step flashing and is sent sideways along the wall, where it runs down behind the siding and into the wall cavity. From inside the house this damage stays hidden for years, finally showing up as a mystery soft spot in the drywall behind the chimney, or a band of mold along the lower sidewall, or worst case structural rot in the rim joist.
A kick-out flashing piece slides under the bottom step flashing and extends out from the wall at roughly a 110-degree angle, redirecting the water flow path away from the wall and into the open end of the gutter. The whole installation takes about thirty minutes and costs less than $40 in materials. It also prevents tens of thousands of dollars in eventual water damage.
Where should kick-out flashing be installed?
Anywhere a sloped roof eave terminates next to a vertical wall that has a gutter underneath. The most common locations:
- Where a one-story roof butts into a two-story sidewall. Classic kick-out location. Every new build needs one. Every re-roof should add one if missing.
- Where a porch roof or sunroom roof terminates against the main house wall. Same physics, smaller scale.
- Where a dormer wall ends above a lower roof with a gutter. Less common but still applies.
- Where any chimney sidewall ends above an eave with a gutter. Add kick-out where the last step flashing meets the gutter line.
When was kick-out flashing required by code?
2009. Kick-out flashing was formally added to the International Residential Code in 2009 under section R903.2.1, which requires diverter flashing at roof-to-wall intersections where a gutter is present. Houses built before 2009 routinely do not have kick-out flashing because it was not yet a code requirement, even though the physics was always the same. Virginia and Maryland adopted the 2009 IRC, so new construction since then has been required to include kick-out, but enforcement has been inconsistent and a surprising number of post-2009 houses still lack it.
This means: if your house was built before 2009, you almost certainly do not have kick-out flashing. If it was built after 2009, you should still verify, because not every framer or roofer installed it correctly.
How much does kick-out flashing cost to install?
Adding kick-out flashing during a roof replacement is essentially free: the materials cost $20 to $40 per location and the labor is included in the base roofing price. Adding it as a retrofit when the roof is not being replaced costs $150 to $400 per location depending on access and whether siding has to come off to install it correctly.
The cost of NOT having it: a typical hidden water-damage repair behind a sidewall (mold remediation, drywall, framing, sheathing, paint) runs $4,500 to $18,000.
What DreamHome installs
DreamHome installs pre-formed aluminum kick-out flashing at every roof-to-wall-with-gutter junction on every roof replacement, included in the base price with no upcharge. On retrofits where the roof is not being replaced but the homeowner is seeing wall damage from a missing kick-out, DH installs a copper or aluminum kick-out under the bottom step flashing without disturbing the siding above. The wall cavity is inspected for existing moisture damage before reinstall.
Red flags on someone else’s roof
Walk around the perimeter of any roof being inspected and look at every spot where a sloped eave terminates next to a wall above a gutter. Here is what to watch for:
- No kick-out at all. The step flashing ends at the gutter and there is no angled diverter piece. By far the most common failure on any house built before 2009 and many built after.
- Black or green staining on the siding directly below the last step flashing. The water signature of a missing kick-out. The wall is already taking damage.
- Cracked stucco directly below the step flashing termination. Stucco walls + missing kick-out is the catastrophic combination; mold develops within two to three winters.
- Caulk smeared along the bottom of the step flashing. A budget contractor’s “fix” instead of installing a real kick-out. Sealant fails within five years.
- Kick-out cut too short or installed flat against the wall. The kick-out needs to extend out at roughly 110 degrees to actually divert water into the gutter. Installed flat, it does almost nothing.