Inspecting Step and Kick-Out Flashing at Roof-Wall Intersections
by Nick Gromicko, CMI® and Ben Gromicko
According to InterNACHI’s Home Inspection Standards of Practice, a home inspector is required to inspect the flashing at the roof and the exterior. Let's learn about what a successful installation of step and kick-out flashing at roof-wall intersections looks like.
Wall flashing and kick-out diverters are required in the 2009 and 2012 International Residential Code (IRC) Section R703.8 and 2015 IRC Section R703.4.
Figure 1. Missing kick-out flashing causing water stains along a chimney stack
Deluging 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, much of this water is channeled along the wall to a gutter. If sidewall flashing is lacking or inadequate, water runoff can get inside the wall and cause serious damage. In big storm events, rainwater can often overflow the gutter and stream down the walls. Diverters are sometimes fashioned on site in an attempt to direct this water into the gutters. If undersized, these diverters are not very helpful. If not properly integrated with the existing housewrap 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, such as fiber cement, vinyl siding, and brick veneer, can mask the evidence for years.
Although all shingle manufacturers recommend step flashing at sidewalls, some jurisdictions located in areas designated high-wind (like Miami-Dade and Broward Counties in Florida) require sidewall flashing to be continuous because it's more wind-resistant.
According to 2014 Florida Building Code, Section R905.2:
Flashing against a vertical sidewall shall be by the step flashing method or continuous L-flashing method.
Figure 2. Missing kick-out flashing at a chimney stack
Anywhere roof sections adjoin wall sections, step flashing should be used to keep water from entering the walls, and kick-out diverters should be used to direct the rainwater into rain gutters where it can be carried away from the structure. Proper flashing that is correctly integrated with housewrap and cladding along roof-wall intersections, and kick-out diverters that are seamless and adequately sized to direct flowing water into the rain gutters are important tools to keep the wall cladding from being saturated by flowing water. Kick-out diverters can be formed on site from sheet metal, but these are often inadequately sized and have unsealed seams that fail over time. Large, seamless, plastic kick-out diverters are commercially available. Roofers working in coordination with housewrap and siding installers should install the step flashing and kick-out diverters.
Home inspectors can look for the following:
- Step-flashing should be installed at sidewalls.
- Headwalls should have fabricated headwall flashing.
- Kick-out flashing should be installed at the base of sidewalls where the sidewall extends past the roof termination.
- Boot or collar flashing should be installed at HVAC combustion, dryer, attic, and plumbing vents to prevent roof leaks.
- Corrosion-resistant flashing pieces should be installed in an overlapped shingle fashion.
- Step flashing should be extended at least 4 inches up the wall from the roof deck and at least 4 inches out along the roof deck (2015 International Residential Code [IRC]).
- Step flashing should be integrated with the drainage plane above (for example, overlap housewrap over it).
- Step flashing, if made of metal, should be galvanized steel at least 0.019-inches thick (IRC 2015).
- Roof felt should be installed prior to installing the step and kick-out flashing.
- House siding should be installed over the step flashing, ending at least 1 inch above the roof surface.
- Roof shingles should be installed over the portion of step flashing on the roof.
- If the roof is metal or rubber membrane, continuous flashing should be used, rather than pieces of step flashing.
- Kick-out flashing should be installed at the end of a roof-wall intersection to divert water away from the wall and into gutters.
- The kick-out flashing should be large enough to handle expected stormwater flows.
Sidewall Step and Kick-Out Diverter Flashing Installation with Rigid Foam Insulation Sheathing
Here is a step-by-step procedure on how sidewall step and kick-out diverter flashing should be installed on houses with rigid foam insulation.
Figure 3. The drip edge and roof underlayment should be applied over the roof deck and continue lapping up the sidewall and over the water-resistive barrier (in this case, rigid foam insulation) a minimum of 7 inches (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
Figure 4. The shingle starter strip should be installed at the roof eave in accordance with the roofing manufacturer’s instructions (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
A seamless, one-piece, non-corrosive kick-out diverter should be positioned and installed as the first piece of step flashing. The kick-out diverter should be positioned on the roof plane where the starter trough stops at the shingle starter strip. The diverter must be flat on the roof and flush to the sidewall. The diverter should be fastened and sealed to the roof deck and starter strip.
Figure 5. The first row of shingles and next section of sidewall flashing should be installed over the up-slope edge of the diverter, lapping a minimum of 4 inches over the diverter. The sidewall flashing height requirement should be determined by a design professional and local building codes (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
Figure 6. The remaining sidewall flashing, appropriate counter flashing, and shingles should be installed in accordance with the manufacturer’s instructions (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
Figure 7. Self-adhesive flashing should be applied over the top edge of the wall flashing, diverter, and rigid foam insulation (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
Figure 8. Construction tape should be applied over the self-adhered flashing, The siding should be installed over the rigid foam insulation (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
Sidewall Step and Kick-Out Diverter Flashing Installation with Wood Sheathing
Here is a step-by-step procedure on how sidewall step and kick-out diverter flashing should be installed on houses with housewrap over oriented strand board (OSB) or plywood sheathing.
Figure 9. The drip edge and roof underlayment should be applied over the roof deck. The underlayment should continue lapping up the sidewall and over the weather-resistive barrier (in this case, housewrap) a minimum of 6 inches (from the U.S. Department of Energy’s Building America Best Practices Series Volume 11).
Figure 10. The shingle starter strip should be installed at the roof eave in accordance with the roofing manufacturer’s instructions (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
The seamless one-piece non-corrosive kick-out diverter should be positioned and installed as the first piece of step flashing. The kick-out diverter should be positioned where the starter trough stops at the shingle starter strip. The diverter must be flat on the roof and flush to the sidewall. The diverter should be fastened and sealed to the roof deck and starter strip.
Figure 11. The first shingle and next section of sidewall flashing should be installed over the up-slope edge of the diverter, lapping a minimum of 4 inches over the diverter. The sidewall flashing height requirement should be determined by a design professional and local building codes (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
Figure 12. The remaining sidewall flashing, appropriate counter flashing, and shingles should be installed in accordance with manufacturer’s instructions (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
Figure 13. Self-adhesive flashing should be applied over the top edge of the wall flashing, diverter, and housewrap (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
Figure 14. The housewrap should be installed to fit over the self-adhesive flashing and sidewall flashing. The housewrap should be cut to fit over diverter with the top of the cut taped, and the siding should be installed over the housewrap (from the U.S. Department of Energy’s Building America Best Practices Series, Volume 11).
Figure 15. Kickout flashing inspection image taken at the InterNACHI
House of Horrors. This is a properly installed kickout flashing with moisture-drainage EIFS.
Figure 16. Kickout flashing inspection image taken at the InterNACHI House of Horrors. This is a properly installed kickout flashing with moisture-drainage EIFS.
Figure 17. Kickout flashing inspection image taken at the InterNACHI
House of Horrors. This is a properly installed kickout flashing with moisture-drainage EIFS.
Summary
Where roofs intersect walls is a critical point for flashing to be installed in order to prevent water leaks and damage. While wood siding may show evidence of this water intrusion, with peeling paint or staining, some wall claddings, such as fiber cement, vinyl siding, and brick veneer, can mask the evidence for years. Flashing and diverters must be correctly integrated with housewrap, cladding, and gutters to prevent water damage. Home inspectors may check for step flashing and roof-wall water deflectors that help drain water away from high-risk corners where walls meet roofs.
This article was sourced primarily from the U.S. Department of Energy and InterNACHI.
