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Kickout Flashing: Stopping Leaks Where a Roof Meets a Wall

  • Published November 7, 2026

A kickout is a small angled piece of flashing at the bottom of a roof-wall joint that turns runoff away from the wall and into the gutter, and DOE building guidance calls for one at the end of a roof-wall intersection. Without it, the water released at that corner can run down the face of the wall and behind the siding, where damage builds out of sight.

You can check for kickouts from the ground in one walk around the house. The corners that lack one are the ones to watch, and the fix, when it is needed, is a job for both a roofer and a siding contractor.

What a Kickout Does at the Bottom of a Roof-Wall Joint

Where a sloped roof runs along a side wall, step flashing carries the water down the slope, one shingle course at a time, keeping it off the wall. The trouble starts where the roof edge ends but the wall keeps going down. The water leaving the last piece of step flashing has nowhere to go but straight down the wall, and if the gutter end sits short of the corner, that water lands on siding instead of in the gutter.

A kickout solves that one spot. It is a piece of metal bent to stick out from the wall at the bottom of the joint, angled so the water is thrown away from the siding and into the gutter. DOE’s Building America guidance on step and kick-out flashing at roof-wall intersections, updated September 14, 2020, puts it in one sentence: “Install kick-out flashing at the end of a roof-wall intersection to divert water away from the wall and into gutters.”

It is one piece of the flashing set that runs along every roof-wall joint; step flashing and the other types are explained in roof flashing types and how each fails, and the guide to roof components names each part around it.

Where Your House Needs One

Look for any corner where a lower roof edge ends against a taller wall, such as:

  • A garage or porch roof whose eave runs into a two-story wall
  • A one-story section of the house meeting a two-story section
  • A shed roof or addition built against an existing wall
  • A roof over a bay or entry that ends against the main wall

If the corner is where an addition or porch roof meets the house, see also tying a new roof into an existing roof.

The code points at the same spot. Seattle’s residential code, Chapter 9, one city’s adopted version of the model International Residential Code (IRC), carries section R903.2.1: “A flashing shall be installed to divert the water away from where the eave of a sloped roof intersects a vertical sidewall.” The code text does not use the word kickout, but that diverter is what it describes.

Enforcement on existing homes differs. The City of Hopkins, Minnesota explains its kick out flashing policy under R903.2.1: kickouts are required “when simultaneously re-siding and re-roofing existing buildings and structures,” and “Kick-out flashings are not required when only re-roofing existing buildings and structures.” Your city may draw the line elsewhere, so ask the building department whether a kickout is required for the work you are planning.

Each kickout needs somewhere to send its water. If the gutter at that corner stops short, is undersized, or is missing, the kickout throws water onto whatever is below. How the gutter at that corner should be sized and placed is covered in the gutter at a roof-wall corner.

The Wall Damage a Missing Kickout Leaves

The water a missing kickout releases goes down the wall, and siding is not a sealed surface. It gets into laps, joints and the edges of trim, and from there to the sheathing and framing behind. Because that happens behind the cladding, the first signs show up on the surface below the corner or on the inside of the wall.

Look for these, starting directly below the corner and working down:

  • Streaks, stains or algae on the siding below the corner
  • Peeling or blistered paint on siding or trim there
  • Siding or trim that is swollen, soft or crumbling
  • Rot at the bottom of the wall, a window below the corner, or the sill
  • Inside the house, stains on the wall below the corner, damaged baseboard, or a musty smell

Moisture in a wall feeds mold. EPA’s Brief Guide to Mold, Moisture and Your Home, last updated February 18, 2026, says “The key to mold control is moisture control,” and advises drying water-damaged areas and items within 24 to 48 hours to prevent mold growth. Inside a wall, that drying cannot happen on its own once water keeps coming, which is why the source has to be stopped.

If water shows up indoors and you are not sure it comes from this corner, tracing an interior leak to its source walks through the method before you open anything up.

Checking for Kickouts From the Ground

You do not need to climb to check. Home inspectors following the InterNACHI Standards of Practice, last revised October 2022, inspect the roof “from ground level or the eaves,” and the kickout check is a ground-level job. Work around the house in order:

  1. Walk the full perimeter and mark every corner where a roof edge ends against a wall. Include porch, garage and dormer roofs.
  2. At each corner, look with binoculars for a metal piece at the bottom of the roof-wall joint that sticks out from the wall and points into the gutter.
  3. Look at the gutter end there. Note whether the gutter reaches the corner or stops short.
  4. Look at the siding and trim below the corner for the damage signs listed above. Where the wall is within reach from the ground, press the siding gently to feel for softness.
  5. Photograph each corner, close and wide, and label the photos by location.
  6. Inside the house, check the wall below each corner for stains or soft drywall.

Other checks you can make without leaving the ground are covered in the no-climb inspection walk-through.

Adding a Kickout to an Existing Roof

A kickout has to lap correctly with three things: the shingles and step flashing above it, the wall’s water-resistive barrier, and the siding over that barrier. That is why it cannot simply be screwed onto the face of a finished wall. Installed correctly, it sits under the barrier and siding above it, so water running down the wall’s hidden layers is also turned out.

A retrofit, then, involves:

  • Opening the siding at the corner
  • Lifting or removing the lowest shingles and step flashing near the wall
  • Installing the kickout and lapping it with the step flashing
  • Repairing any rotted sheathing or framing found behind the siding
  • Restoring the water-resistive barrier so it laps over the kickout
  • Reinstalling or replacing the siding and trim

That makes it a two-trade job, roofing and siding, and each handoff between the trades needs a named owner. Ask for a retrofit quote that names who opens the siding, who installs and laps the kickout, who repairs any rot, who restores the barrier, and who warrants the corner afterward. If the work is split between a roofer and a siding contractor, or subcontracted, how two trades share one job covers the supervision and insurance questions to settle first.

Masonry and stucco walls handle water differently from lapped siding, so if your corner meets one of those, ask the contractor how the kickout will tie into that wall’s drainage layer before you agree to a method.

Do You Need a Kickout Retrofit Now?

If a corner has no kickout and you see staining, soft siding or interior damage below it, retrofit now; the damage keeps growing while water keeps reaching the wall. If a corner has no kickout but shows no damage, add one at your next roof or siding job, when the siding and shingles at that corner are open anyway. If you are re-siding and re-roofing together, ask the building department whether a kickout is required at each roof-wall corner, since some jurisdictions enforce it then.

Start with the perimeter walk, binoculars and camera in hand, before the next heavy rain.

This guide is general information for U.S. homeowners, not legal, insurance, tax, or engineering advice. Codes, laws, and policy terms vary by location and change over time; confirm details with your local building department, your insurer, or a licensed professional.

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