Step and Kick-Out Flashing at Roof-Wall Intersections

    Scope Images
    Image
    Step and kickout flashing should be installed at all roof-wall intersections to protect the wall and divert rainwater runoff into a gutter.
    Scope

    Install step and kick-out flashing at all roof-wall intersections to protect walls from water intrusion and install boot or collar flashing at all roof penetrations to protect roofs from leaks.

    • Install corrosion-resistant flashing pieces that are overlapped shingle fashion.
    • Extend step flashing at least 4 inches up the wall from the roof deck and at least four inches out along the roof deck (IRC 2015) and integrate the flashing with the drainage plane above (for example, overlap house wrap over it). 
    • If metal, the flashing should be made of galvanized steel at least 0.019-inches thick (IRC 2015).
    • Install roof felt prior to installing the step and kick-out flashing.
    • Install house siding over the step flashing, ending at least one inch above the roof surface.
    • Install shingles over the portion of step flashing on the roof.
    • When installing metal or rubber membrane roofs, use continuous flashing rather than pieces of step flashing.
    • Install kick-out flashing at the end of a roof-wall intersection to divert water away from the wall and into gutters. Ensure that the kick-out flashing is large enough to handle expected storm water flows. 
    • Install boot or collar flashings around all roof penetrations and properly integrate with roof membranes and shingles above and below the penetration. 

    See the Compliance Tab for related codes and standards requirements, and criteria to meet national programs such as DOE’s Zero Energy Ready Home programENERGY STAR Certified Homes, and EPA Indoor airPLUS.

    Description

    Heavy rains can pour thousands of gallons of water onto a home’s roof in a single storm. In multi-level house designs where roofs intersect walls, this roof-wall intersection will channel much of this water to drain off the roof and usually into a gutter. If sidewall flashing is lacking or inadequate, water can leak into the wall and cause serious water damage. In big storm events, rainwater can often overflow the gutter and stream down the walls. Diverters are sometimes fashioned onsite in an attempt to direct this water into the gutters. If undersized, these diverters are not very helpful. If not properly integrated with the WRB (water-resistant barrier, e.g., house wrap) and cladding, they can do more harm than good by allowing water inside the wall cavities. The result can be significant damage to wall sheathing, framing, and insulation, and mold inside the wall cavities. While older wood siding would show evidence of this water intrusion by peeling paint, new wall claddings like fiber cement, vinyl siding, and brick veneer can mask the evidence for years.

    Flashing is required at roof-wall intersections (step flashing) and to divert water away from where the eave of a sloped roof intersects a vertical sidewall (kick-out flashing). Where flashing is metal, the metal shall be corrosion resistant with a thickness if not less than 0.019 inch (26-gauge galvanized sheet) (2018 IRC R903.2.1).  To be effective, all flashing must be integrated with the roof and wall drainage planes shingle-fashioned, where the top layer of the WRB or flashing laps over the bottom layer to prevent water draining behind the bottom layer.

    Kick-out flashing directs rainwater into rain gutters where it can be carried away from the structure. Kick-out flashing, also referred to as diverters, can be fabricated on site using sheet metal but these can be undersized and may have unsealed seams that allow leakage. Prefabricated kick-out flashings are available as seamless, molded plastic pieces or metal with welded seams.

    These materials would be installed by roofers in coordination with house wrap and siding installers. This task should be included in the contract for the appropriate trade depending on the workflow at the specific job site.

    Step flashings and kick-out diverters are required in the 2009 and 2012 IRC (R703.8) and 2015 and 2018 IRC (R703.4; R903.2.1). See the Compliance tab.

    Improper flashing can allow rain water into walls, causing significant damage.
    Figure 1. Improper flashing can allow rain water into walls, causing significant damage.

     

    How to Install Sidewall Flashing and Kick-Out Diverters — On Homes with Rigid Foam Insulation Sheathing

    1. Install the drip edge and roofing underlayment over the roof deck and lap the underlayment up the sidewall and over the rigid foam insulation a minimum of 8 inches (Figure 2).
    2. Install the shingle starter strip at the roof eave in accordance with the roofing manufacturer’s instructions (Figure 3).
      1. Place the seamless, one-piece, non-corrosive kick-out diverter as the first piece of step flashing.
      2. Slide the kick-out diverter up the roof plane until the starter trough stops at the shingle starter strip. The diverter must be flat on the roof and flush to the sidewall (Figure 3).
      3. Fasten and seal the diverter to the roof deck and starter strip. (Do not fasten it to the sidewall.)
    3. Place the first row of shingles and next section of sidewall flashing over the up-slope edge of the diverter, lapping a minimum of 4 inches over the diverter (Figure 4). Sidewall flashing height requirement should be determined by a design professional and local building codes.)
    4. Install the remaining sidewall flashing, appropriate counter flashing, and shingles in accordance with the manufacturer’s instructions (Figure 5).
    5. Apply self-adhesive flashing over the top edge of the wall flashing, diverter, and rigid foam insulation (Figure 6).
    6. Apply construction tape over the self-adhered flashing (Figure 7).
    7. Apply siding over the rigid foam insulation.
    Step 1: apply roof underlayment.
    Figure 2. Apply roof underlayment over roof deck and up sidewall over the rigid foam insulation.

     

    Step 2. Install shingle starter strip then kick-out diverter as first piece of step flashing.
    Figure 3. Install shingle starter strip then kick-out diverter as first piece of step flashing.

     

    Step 3. Place the first shingle and the next section of sidewall flashing over upper edge of diverter.
    Figure 4. Place the first row of shingles and the first piece of flashing over the upper edge of the diverter.

     

    Step 4. Install remaining sidewall flashing, appropriate counter flashing, and shingles.
    Figure 5. Install remaining sidewall flashing and roof shingles.

     

    Step 5. Apply self-adhesive flashing over top edge of the wall flashing, diverter, and rigid foam insulation.
    Figure 6. Apply self-adhesive flashing over the top edge of the wall flashing, the diverter, and the rigid foam insulation.

     

    Step 6. Apply construction tape over the self-adhered flashing.
    Figure 7. Apply construction tape over the self-adhered flashing.

     

     

    How to Install Sidewall Flashing and Kick-Out Diverters — On Homes with House Wrap over OSB or Plywood Sheathing

    1. Apply drip edge and roof underlayment over the roof deck (Figure 8). Continue lapping up the sidewall and over the weather-resistive barrier (in this case house wrap) a minimum of 6 inches. A good construction practice is to leave a 1-inch gap between the vertical wall and fascia to accommodate the house wrap below the roof line.
      Install the shingle starter strip at the roof eave in accordance with the roofing manufacturer’s instructions (Figure 9).
      1. Place the seamless one-piece non-corrosive kick-out diverter as the first piece of step flashing.
      2. Slide the kick-out diverter up the roof plane until the starter trough stops at the shingle starter strip. The diverter must be flat on the roof and flush to the sidewall.
      3. Fasten and seal the diverter to the roof deck and starter strip. (Do not fasten it to the sidewall.)
    2. Place the first shingle and next section of sidewall flashing over the up-slope edge of the diverter, lapping a minimum of 4 inches over the diverter as shown in Figure 10. (The sidewall flashing height requirement should be determined by a design professional and local building codes.)
    3. Install the remaining sidewall flashing, appropriate counter flashing, and shingles in accordance with manufacturer’s instructions (Figure 11).
    4. Apply self-adhesive flashing over the top edge of the wall flashing, diverter, and housewrap (Figure 12).
    5. Install the housewrap. Cut the housewrap to fit over the self-adhesive flashing and sidewall flashing (Figure 13). Note that these subsequent layers of house wrap, shown in Figure 13, will be installed shinhle-fashion over the roofing underlayment, kick-out flashing, and base flashing. If house wrap and roofing are installed by different tradeds, it is important to coordinate this effor to maintain the drainage plane.
    6. Apply siding over the housewrap.

       

    Apply roof underlayment over roof deck and up the sidewall over housewrap.
    Figure 8. Apply roof underlayment over roof deck and up the sidewall over housewrap. (Source: Dryflekt 2015.)

     

    Install shingle starter strip then kick-out diverter; attach to roof deck but not sidewall.
    Figure 9. Install shingle starter strip then kick-out diverter; attach to roof deck but not sidewall. (Source: Dryflekt 2015.)

     

    Place first shingle and next section of sidewall flashing over upper edge of diverter.
    Figure 10. Place first shingle and next section of sidewall flashing over upper edge of diverter. (Source: Dryflekt 2015.)

     

    Install remaining sidewall flashing, counter flashing, and shingles.
    Figure 11. Install remaining sidewall flashing, counter flashing, and shingles. (Source: Dryflekt 2015.)

     

    Apply self-adhesive flashing over top edge of the wall flashing, diverter, and housewrap.
    Figure 12. Apply self-adhesive flashing over top edge of the wall flashing, diverter, and housewrap. (Source: Dryflekt 2015.)

     

    Install the housewrap. Cut housewrap to fit over diverter and tape top of cut.
    Figure 13. Install the housewrap. Cut housewrap to fit over diverter and tape top of cut. (Source: Dryflekt 2015.)

     

    Ensuring Success

    The site supervisor should visually inspect the step flashing and kickout diverter during installation by trades to ensure that it is properly integrated with other wall and roof elements.

    Climate

    Hurricane-Prone Regions

    Roofing and wall cladding are more likely to be damaged or lost in hurricane-prone regions and other high-wind areas, leaving flashing and underlayment exposed and more susceptible to wind and water intrusion. Proper installation of flashing and sealing products is even more important in these areas to protect against storm damage.

    The IRC does not have additional requirements for roof-wall flashing in hurricane-prone regions or other high-wind areas. Some local jurisdictions may have additional requirements or require specific product approval. Building codes establish minimum requirements, but products must also be installed in accordance with manufacturer’s instructions. This is important because codes typically do not provide all of the detailed information for a durable installation. Assessments by FEMA after hurricanes commonly find that water intrusion and structural building failures are due to improper installation of building components. So, even where the IRC does not require additional measures, proper installation is more critical in hurricane-prone regions.   

    The Insurance Institute for Business and Home Safety® (IBHS) Fortified Home program offers guidance, best practices, and voluntary construction standards and programs for building in disaster-prone areas including hurricane and other high-wind zones. The IBHS FORTIFIED Roof™ program includes options for sealed roof decks.  IBHS also provides specific guidance for flashing roof-wall intersections.   

    Roof Drainage

    The 2018 IRC requires roof water to be collected and discharged to the ground surface (i.e., rain gutters and downspouts) not less than 5 feet away from foundation walls or to an approved drainage system in areas where expansive soils or collapsible soils are known to exist (R801.3). Rain gutters are not necessarily required for other soil conditions but still may be necessary for proper site drainage requirements to direct water away from the foundation (R401.3). 

    The IRC does not have capacity, construction, or installation requirements specific to rain gutters.  IBHS guidance in hurricane and high-wind areas addresses maintenance for gutters and downspouts but not sizing or attachment details.  Local jurisdictions may have additional requirements or require specific product approval (e.g., see the Florida requirements below). 

    2020 Florida Residential Code

    R903.4.2 One- and two-family dwellings and private garages. When gutters and leaders are placed on the outside of the buildings, the gutter and leaders shall be constructed of metal or approved plastic for outdoor exposure with lapped, soldered or caulked joints and shall be securely fastened to the building with a corrosion resistant fastening device of similar or compatible material to the gutters or downspouts.

    Right and Wrong Images
    Image
    Wrong – The step flashing is not the required height above the roof deck
    Wrong – The step flashing is not the required height above the roof deck
    Image
    Right – The step flashing is the correct height above the roof deck
    Right – The step flashing is the correct height above the roof deck
    Image
    Wrong – the water-resistant barrier is layered underneath the step flashing, which could allow water to get behind the step flashing and into the wall.
    Wrong – the water-resistant barrier is layered underneath the step flashing, which could allow water to get behind the step flashing and into the wall.
    Image
    Right – The water-resistant barrier is layered over the step flashing to provide a complete drainage system
    Right – The water-resistant barrier is layered over the step flashing to provide a complete drainage system
    Image
    Right - Step flashing along a chimney is integrated in a layered manner with asphalt shingle roofing and topped with counterflashing that is embedded into brick mortar joint above
    Right - Step flashing along a chimney is integrated in a layered manner with asphalt shingle roofing and topped with counterflashing that is embedded into brick mortar joint above
    Videos
    Publication Date
    Author(s)
    Fine Homebuilding
    Organization(s)
    Fine Homebuilding
    Description
    When flashing one of a house’s biggest potential leaks — where the eave overhang meets a vertical wall — editorial advisor Mike Guertin chooses to err on the side of caution to control water flow and not rely solely on step flashing.
    Publication Date
    Author(s)
    Weather Proofing America
    Organization(s)
    Weather Proofing America
    Description
    Video explaining how to correctly install wall-to-roof flashing and kick-out flashing to protect walls from rain water damage.
    CAD
    CAD Files
    Kick-Out Diverter Flashing Detail
    Kick-Out Diverter Flashing Detail
    Download: DWG PDF

    Compliance

    The Compliance tab contains both program and code information. Code language is excerpted and summarized below. For exact code language, refer to the applicable code, which may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.

     

    ENERGY STAR Certified Homes, Version 3/3.1 (Rev. 09)

    Water Management System Builder Requirements

    3. Water-Managed Roof Assembly.
    3.1 Step and kick-out flashing at all roof-wall intersections, extending ≥ 4” on wall surface above roof deck and integrated shingle-style with drainage plane above; boot / collar flashing at all roof penetrations.12

    Footnote 12) Intersecting wall siding shall terminate 1 in. above the roof or higher, per manufacturer's recommendations. Continuous flashing shall be installed in place of step flashing for metal and rubber membrane roofs.

    Please see the ENERGY STAR Certified Homes Implementation Timeline for the program version and revision currently applicable in in your state.

     

    DOE Zero Energy Ready Home (Revision 07)

    Exhibit 1 Mandatory Requirements.
    Exhibit 1, Item 1) Certified under the ENERGY STAR Qualified Homes Program or the ENERGY STAR Multifamily New Construction Program.

     

    2009 International Residential Code (IRC)

    Section R703.8 Flashing. Approved corrosion-resistant flashing to be applied shingle-fashion to prevent water from entering into wall cavities or from penetrating into building structural framing components. Self-adhered flashing must comply with AAMA 711. Flashing at exterior window and door openings must extend to the surface of the exterior wall finish or to the water-resistive barrier.  Corrosion-resistant flashings should be installed:

    • Exterior and window door openings and extend to the exterior wall finish surface or water-resistive barrier
    • At intersection of chimneys or other masonry construction with frame or stucco walls, with projecting lips on both sides under stucco copings
    • Under and at ends of masonry, wood, or metal copings and sills
    • Continuously above all projecting wood trim
    • Where exterior porches, decks, or stairs attach to a wall or floor assembly (wood-frame construction)
    • At wall and roof intersections
    • At built-in gutters.

    2012 IRC

    Section R703.8 Flashing. Approved corrosion-resistant flashing to be applied shingle-fashion to prevent water from entering into wall cavities or from penetrating into building structural framing components. Self-adhered flashing must comply with AAMA 711. Flashing at exterior window and door openings must extend to the surface of the exterior wall finish or to the water-resistive barrier. Flashing must be installed at the following locations:

    • Exterior window and door openings
    • In accordance with fenestration manufacturer’s installation and flashing instructions or in accordance with the flashing manufacturer’s instructions. Where instructions or details aren’t provided, pan flashing is to be installed at the sill of exterior window and door openings and must be sealed or sloped to direct water to the surface of the exterior wall finish or water-resistive barrier. Openings using pan flashing must also incorporate flashing or protection at the head and sides.
    • Per the flashing design or method of a registered design professional.
    • Under other approved methods.
    • Exterior and window door openings and extend to the exterior wall finish surface or water-resistive barrier
    • At intersection of chimneys or other masonry construction with frame or stucco walls, with projecting lips on both sides under stucco copings
    • Under and at ends of masonry, wood, or metal copings and sills
    • Continuously above all projecting wood trim
    • Where exterior porches, decks, or stairs attach to a wall or floor assembly (wood-frame construction.
    • At wall and roof intersections
    • At built-in gutters.

    20152018, and 2021 IRC

    Section R703.4 Flashing. Approved corrosion-resistant flashing to be applied shingle-fashion to prevent water from entering into wall cavities or from penetrating into building structural framing components. Self-adhered flashing must comply with AAMA 711. Fluid-applied membranes shall comply with AAMA 714. Flashing must be installed at wall and roof intersections and at built-in gutters.

    Chapter 9 Roof Assemblies, Section R903.2. Flashing is required at wall and roof intersections and to divert water away from where the eave of a sloped roof intersects a vertical sidewall.  Where flashing is metal, the metal shall be corrosion resistant with a thickness of not less than 0.019 inch (26-gauge galvanized sheet).

    Retrofit:  2009, 2012, 2015, 2018,  and 2021 IRC

    Section R102.7.1 Additions, alterations, or repairs. Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing building to comply with the requirements of this code, unless otherwise stated. (See code for additional requirements and exceptions.)

    Appendix J regulates the repair, renovation, alteration, and reconstruction of existing buildings and is intended to encourage their continued safe use.

     

    2020 Florida Residential Code

    R903.4.2 One- and two-family dwellings and private garages. When gutters and leaders are placed on the outside of the buildings, the gutter and leaders shall be constructed of metal or approved plastic for outdoor exposure with lapped, soldered or caulked joints and shall be securely fastened to the building with a corrosion resistant fastening device of similar or compatible material to the gutters or downspouts.

     

    American Architectural Manufacturers Association (AAMA) 711-13

    AAMA 711-13. Voluntary Specification for Self Adhering Flashing Used for Installation of Exterior Wall Fenestration Products. Available from AAMA’s online store from the link above. The specification establishes the test methods and minimum performance requirements for self adhering flashing products used around the perimeter of exterior fenestration products.  It also provides a method to determine the minimum width of the flashing products and to evaluate the influence of the environmental factors on the installation of self adhering flashing products applied under typical field conditions. 

    Existing Homes

    SCOPE

    Before starting any retrofit project, consult the pre-retrofit assessment guides in the existing homes tool.

    Install step and kick-out flashing at roof-wall intersections

    • Remove existing siding and shingles at roof-wall intersection.
    • Remove and repair any damaged siding and sheathing next to or beneath the roof-wall intersection.
    • Install liquid water proofing or peel and stick membrane on walls next to and beneath the end of the roof-wall intersection.
    • Install kick-out and step flashing and lap correctly to direct water out from wall; integrate it properly with existing house wrap.
    • Replace siding over step flashing.

    DESCRIPTION

    Missing kick-out and step flashing has been responsible for thousands of dollars worth of damage for homeowners. Signs of potential trouble include streaks of discoloration, mold or algae along walls below wall-roof intersections, rotting wood, or peeling paint. However with newer siding surfaces such as fiber cement and vinyl siding, there may be no visible exterior signs of damage even when water is pouring into the wall during every storm event and causing interior rot and mold inside the wall cavity.

    The first step is to inspect the outside of the home and note all roof-wall intersections. Look for step flashing and kick-out flashing at those roof-wall intersections.

    The step flashing should extend along the whole length of the roof-wall juncture. The individual pieces of metal flashing should be set so that each piece overlaps the piece beneath it; underlapped pieces can inject water into the wall rather than deflecting water from the wall. The step flashing should be visible below the siding because siding installers should leave a .75- to 1.5-inch gap between the siding and the roof below. This gap can get covered over if the home has been roofed over since the siding was installed, thus building up the roof height. When reroofing, it is best to remove and replace the step flashing to ensure it lays flat and is correctly aligned. If you are not reroofing, alternate the flashing with the existing shingles. Start from the bottom with kick-out flashing, as described in the Description tab. Along the wall, remove or cut away siding a few inches up the wall. Fold back any intact existing house wrap and install peel and stick membrane on the wall and roof surface. Install metal flashing that has been bent to a right angle with 5 or more inches extending up the wall and 5 inches extending out along the roof. Install with one nail placed at the top corner of the flashing on the roof or the house wall, but not both, to allow for movement. Install a strip of house wrap along the step flashing that extends up under the house wrap above and down to an inch above the roof, as shown in the Description tab.

    On older homes, if kick-out flashing exists at all, it is often fabricated on site from pieces of flat metal flashing. Inspect existing kick-out flashing to determine if the size and angle are adequate for directing water into the gutter and to see if there are any holes, even pinholes, in the kick-out flashing. Inspect the walls around the kick-out flashing for holes and for rot. If the kick-out flashing is missing or inadequate, remove and replace it. Prefabricated plastic and metal kick-out diverters are commercially available. Install as described in the Description tab. Some installers will recommend just cutting a vertical slit into the wall above the end of the gutter and lifting the bottom course of shingles, then sliding the kick-out flashing into that slot and under the shingle. This is a less-than-adequate fix as the flashing will not be properly integrated with the side flashing or house wrap so the potential for future failure is higher and the ability to see and repair current damage is limited.

    The end of the gutter should not touch the intersecting wall; there should be a small gap to allow free drainage down the wall.

    COMPLIANCE

    See Compliance tab. 

    More Info.

    Access to some references may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.

    Case Studies
    References and Resources*
    Author(s)
    U.S. Environmental Protection Agency
    Organization(s)
    EPA
    Publication Date
    Description
    Guide describing details that serve as a visual reference for each of the line items in the Water Management System Builder Checklist.
    Author(s)
    Hammer & Hand
    Organization(s)
    Hammer & Hand
    Publication Date
    Description
    This Best Practices Manual is the product of Hammer & Hand’s ongoing work to document and internally codify our standard operating procedures for construction practice.
    Author(s)
    Insurance Institute for Business & Home Safety
    Organization(s)
    IBHS Fortified Home
    Publication Date
    Description
    Website providing resources for roofers to construct high-wind, hurricane, and hail-resistant roofs from IBHS Fortified program.
    Author(s)
    Home Innovation Research Labs
    Organization(s)
    HIRL
    Publication Date
    Description
    Fact sheet describing design and construction practices to reduce the likelihood of water intrusion in walls and foundations in residential construction.
    *For non-dated media, such as websites, the date listed is the date accessed.
    Contributors to this Guide

    The following authors and organizations contributed to the content in this Guide.

    Building Science Measures
    Building Science-to-Sales Translator

    Kick-Out Flashing, Step Flashing = Roof-Wall Water Deflector

    Image(s)
    Technical Description

    Where roofs intersect walls is a critical point for flashing to prevent water leaks and damage. While wood siding may quickly show evidence of this water intrusion with peeling paint or staining, some wall claddings like fiber cement, vinyl siding, and brick veneer can mask the evidence for years. Roof step flashing must be effectively integrated with diverters known as kick-out flashing to effectively direct water to the gutters and avoid water damage.

    Roof-Wall Water Deflector
    Sales Message

    Roof-wall water deflectors help drain water away from high-risk corners where walls meet roofs. What this means to you is peace-of-mind knowing your home has a comprehensive set of measures that minimize the risk of water damage in your home. Wouldn’t you agree every home should have full water protection?

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