Kick Out Flashing: The Small Part That Saves Your Siding

Walk the perimeter of almost any older Macomb County house and you will find at least one spot where a roof slope ends against a wall, an eave meeting a dormer, a porch roof tucking under the main house, a garage roofline stopping at the siding. At that exact corner, a small diverter called a kick out flashing is supposed to bend the water shooting off the roof edge outward, into the gutter, instead of letting it run straight down behind the siding. When that one piece is missing, the framing behind the wall can be soaking up water for years before anyone notices, because the damage happens on the inside of the wall, not the outside where you would see it.

01 / THE SHORT ANSWEROne missing piece, years of hidden damage

A kick out flashing is a small L-shaped or diverter-style piece of metal installed at the bottom end of a roof-to-sidewall run, right where the step flashing stops and the gutter or eave begins. Its only job is to kick the sheet of water coming off the roof edge away from the wall instead of letting it pour straight down the siding and behind it. Where one was never installed, and it is a common miss on additions, porches, and dormers built or reroofed without it, the wall behind that corner has been getting wet on a schedule for as long as the house has stood.

The reason this guide exists on its own, separate from our broader roof flashing repair guide, is that a missing kick out rarely shows up as a roof problem at all. It shows up as a siding problem, a stain, or a soft spot near the ground, which sends a lot of homeowners chasing the wrong contractor for years before someone finally traces it back to the roof edge.

02 / THE MECHANISMWhat a kick out actually does

Picture the step flashing that runs up a sidewall alongside a roof slope, the overlapping metal pieces woven between each course of shingles that keep water on the roof side of the wall. That system works fine all the way up the slope. The problem is the bottom, where the step flashing simply ends and the roof edge meets the gutter or fascia. Without a diverter at that last step, the sheet of water that has been running down the roof and along the wall for the whole length of the slope arrives at that corner with nowhere to go but straight down, directly behind the siding, at the exact point the wall meets the roof.

• A properly installed kick out extends the step flashing outward and downward at that last course, forming a small ramp that throws water past the siding and into the gutter or onto the roof surface below.
• Without it, the same volume of water that a full roof slope collects gets concentrated at one corner and directed behind the wall covering instead of away from it.
• The failure is invisible from the ground for years, because the water goes in behind the siding, not down the face of it, so there is no obvious streak or stain to see from the yard.

Why the damage compounds

A missing kick out does not usually cause a dramatic leak. It causes a slow, steady soak, a little water behind the same few feet of siding every time it rains, for however many years the house has gone without one. That kind of chronic dampness rots sheathing, saturates insulation, and corrodes fasteners well before anyone notices a problem, because none of it shows on the visible siding surface until the rot has progressed enough to soften the wall or push moisture through to the interior. Our roof leak inside a wall guide covers the fuller damage chain once water gets past this point.

03 / THE TELLSHow to spot a missing kick out

The corner to check is any spot where a roof edge stops against a vertical wall, not where it just runs along the top of a wall the whole way. Common locations include a porch roof meeting the house, a garage roofline against siding, a dormer cheek wall, or a lower roof section tucking under a second story. Stand at ground level and look at the wall directly below and slightly downhill of that intersection.

None of these signs are exclusive to a missing kick out. Siding can stain for other reasons, and a soft spot could trace to a gutter that overflows at that same corner. What makes a missing kick out the leading suspect is location: if the stain or softness sits right where a roof edge dies into a wall, that is the textbook spot, and it is worth a look before you assume the siding itself has failed.

Homeowners often replace the siding at that corner two or three times over the years before anyone checks whether a kick out was ever there. The siding was never the problem. The water source above it was.

04 / WHY IT GETS MISSEDWhy so many older Macomb County homes never had one

Kick out flashing has been a recognized detail in residential roofing for decades, but it is a small, easy-to-skip item on a job with dozens of larger line items, and it has historically been inconsistently required and inconsistently installed. A lot of Macomb County housing stock, additions, porches, and dormers in particular, was built or reroofed by crews who ran the step flashing up the wall correctly but never added the diverter at the bottom, either because the detail was overlooked or because a felt-and-caulk shortcut was used instead.

Reroofing projects are also a common place for the detail to get missed a second time. A roofer replacing shingles over an existing wall intersection can reuse or work around old flashing that never had a kick out in the first place, rather than opening the corner up to add one, especially on a lower-cost tear-off where nobody asked specifically about that detail. That is one more reason a full inspection, not just a shingle count, matters when you are evaluating a roof you did not have installed yourself.

05 / THE FIXWhat a kick out retrofit involves, and what it runs

Adding a kick out where one was never installed means opening the last course or two of siding and step flashing at that corner, forming and setting the diverter piece so it ties into the step flashing above and directs water past the wall covering, then closing the siding back up around it. On a roof that is otherwise sound, that is a targeted, same-day repair, not a reroof.

What changes the scope, and the price, is what the crew finds once the corner is opened. If the chronic soaking has already rotted sheathing or wall framing behind the siding, that damaged material has to come out and be replaced before the new flashing and siding go back on, which is the difference between a quick metal swap and a repair that also touches carpentry. Repairs across Macomb County run $350 to $3,200, and larger or complex repairs, including ones that uncover rot, can run higher. A kick out retrofit with no hidden rot typically sits toward the lower end of that range; one that has been leaking unnoticed for years and needs sheathing replaced sits closer to the middle or upper end.

This is exactly the kind of small, high-value repair a free inspection is built to catch. We check every roof-to-sidewall intersection on the house, not just the shingles, and if a corner is missing a kick out, we will show you the photo and the fix before any work starts. You can start the process from the instant estimator, choosing repair as the job type, or call directly for the same free visit.

If you already know the water has traveled further, into a wall cavity, drywall, or ceiling below, our roof leak inside a wall guide covers what that damage chain looks like and how a repair scopes it. For the broader picture of every flashing detail on a roof, our types of roof flashing guide shows where kick outs fit alongside step, valley, and chimney flashing, and our roof flashing repair guide covers the full range of flashing failures we fix. If you would rather see a ballpark before anyone visits, the 60-second cost calculator runs the same published ranges from our pricing page against your numbers, and our roof repair services page covers the rest of what a typical repair visit includes.