 If your have reached this page it's likely either because your home inspector or your home inspection report has mentioned problems with kick out flashings (also known as "kickout" and "kick-out" flashings) or because you have water damage and someone has mentioned a "kick out flashing" (or lack of one) as contributing to your problem. This FAQ is intended to help you understand kick out flashings and their function.
Kick out flashing FAQ
What is the
function of a kick out flashing?
The function of a kick out flashing is to prevent what you see
at the left: a type of "roof" leak which occurs in
a location where it has the potential to create
extensive damage.
To understand what happened to this house, visualize
the path of water flowing down the roof alongside the vertical
wall above it.
When it reached the bottom of the roof, water was able to
penetrate behind the siding and/or overshoot down past the
gutter and onto the wall below - the wall-roof junction
acted as a funnel to concentrate water runoff down the
roof into a stream being directed against the siding at
the roof's edge and beyond.
As you can see, over time that water can do a lot of damage.
This page is about the role of kick out flashings in
preventing or at least minimizing such problems. top
How does a
kick out flashing work?
"Kick out" flashings are intended to prevent water
from flowing behind a wall or down a vertical surface such as
the fascia below a roof's edge by redirecting
it a short distance sideways and onto a roof surface or into a
gutter.
In theory this is simple to do: an "L"
shaped piece of sheet metal or plastic is installed near the edge
of the roof in such a way the water cannot run behind the kick out
and instead is channeled off to one the side, where it falls off
the edge of the roof to the ground or a gutter or other water
collector (see the diagram at left.
In practice there are many possible defects in kick out design
and construction, for example the kick out must be placed behind the step
or other flashing "uphill" of the kick out,
and should be overlapped by any weather resistant
barrier (such as "house wrap") above it.
It can also be expected that occasionally conditions such as
heavy rains or damning by ice and snow will cause water to
overflow the kick out, and provision should be made to
protect wall at the kick out-wall junction - in this
example that's the function of the vertical piece of
"Self-adhering membrane" at the left end of
the kick out.
The example at right illustrates the correct sequence of materials at this retro-fit installation of a kick out to a wall-roof interface above an eave as shown in the diagram above
A layer of waterproof shingle underlayment (WSU) has been placed beside and below the step flashing, with each piece of step flashing overlapping the piece below it. The step flashing in turn overlaps the kick out flashing, and the water resistant barrier (WRB, the blue "housewrap") will be turned back down so that it sits to the outside of the step and kick out flashings.
The siding will then be installed over the WRB, with a 1-2" gap (a "holdback") between the bottom of the siding and the roof surface to allow inspection and maintainance and to make it easier for roofers to properly install replacement shingles in the future.
If any of these installation details are
incorrect the kick out may actually make matters worse by
conducting water into the wall behind the flashing
or under the edge of the roof covering, or by directing
water against a surface which was not intended
to resist high moisture levels.
In the real world, flashings do not always exactly follow
"textbook" examples, especially if it has been
necessary to retro-fit a flashing to correct an existing
problem.
In the picture at left a roofer has added a kick out flashing at
the junction of a roof and dormer. The vinyl siding closest to
the roof was pulled loose and slit to allow the instillation of
the kick out flashing, which was worked up back under the exiting
step flashing and the siding then replaced.
This repair was successful: when it rains water is effectively
directed into the gutter, and moisture levels at the interior of
the wall in this location have returned to normal.
Successful redirection of water under such circumstances can be
a real challenge for roofers and the only real test of such
efforts is their actual performance - some flashings which look
as though they will work well do not, and some flashings which
appear marginal are effective in stopping leaks.
But when you find no kick out flashings at such locations or the
flashings are clearly incorrect or insufficient, expect problems
with water penetration. top
Kick out flashings at dormers and
bays
The low point of the junction of a dormer or bay with a roof
is the "classic" location for water damage caused by a
missing kick out flashing. The roof to wall junctions
below are typical examples - it was possible to predict that
significant damage would likely be present based on absence of
correct flashings, but the extent of the damage was not apparent
until siding had been removed.
The reason such flashing
defects are common at both new construction
and remodeling projects - especially the installation of
vinyl or aluminum siding or fascia and/or soffits or the
repair or replacement of existing roofing - is that
many otherwise skillful installers do not understand
the importance of such flashing or how to install them
correctly. As a result they may damage or remove
existing flashings or fail to correctly install new ones where
required. For this reason all roofs should be
carefully inspected for potential flashing problems
irrespective of condition or the quality of other
aspects of their installation. top
Kick out flashings
at chimneys
After dormers and bays the next most
common location of damage caused by missing or incorrect
kick outs is at chimneys, for example when a chimney runs up
the side of a structure we frequently observe interior and
exterior water problems resulting from improper water control at
the junction of chimney with the roof and gutter:
Damage from a missing kick out at this location can be
particularly severe as water flowing down the side of the chimney
can enter at any defects in the junction between the chimney and
the siding. As a result water damage can extend to areas well
below roof level as water flows down the chimney and/or behind
the siding. Often, as in the case of the chimney above, there have been repeated attempts to caulk gaps between the chimney and the wall cladding, frequently this is an indication that water intrusion at this location has already caused interior damage. top
Kick out
flashings at other locations
Dormers, bays and chimneys are the most
common locations at which we observe damage due to missing or
incorrect kick out flashings, but the same general principles can
apply in many locations where a vertical surface is terminated
above a roof. top
Kick out flashings for specific
materials
Kick out flashings for tile roofs
The "kick out" for the roof wall junction on a tile
roof (darker blue section at left) is often formed into the
downslope end of the sheetmetal pan or channel flashing
underneath the tile at the wall junction (lighter blue).
The counter flashing above the pan (not fully shown in this diagram) normally
extends down over the kick portion of the pan or channel flashing and is overlapped
by the water resistant barrier and the wall cladding above it.
This diagram is an example only, the exact detailing required
will depend on the tile style the manufacturer's recommend
installation procedure, the other roof and wall flashing details,
local practice and local codes. top
Kick out
flashings for stucco
Typical details for a kick out flashing at a stucco wall to
roof junction.
A common installation error is to place the WRB behind these
flashings, in this case water that penetrates the stucco will be
directed behind the flashings. This can result in extensive
damage to the underlying sheathing and wall structural members
before damage becomes apparent at interior or exterior
surfaces.
This diagram is an example only, the exact detailing required
will depend on the type of stucco system, the manufacture's
installation instructions, the other roof and wall flashing
details and local practice and local codes.
Because they are often field-fabricated, kick out flashings at
the junctions between stucco walls and roof surfaces are
particularly prone to incorrect design or installation.
In this case the kick out has a 90 degree bend and is installed
parallel to the eave.
As evidenced by the derbies collecting at the bend the result is
a water back-up at this location when water hits the kick out.
In addition, the crimp toward the roof at the end of the
kick outs arm captures additional debris and channels water done
the inside face of the kick out at this point.
When kick out (or any other type of flashing) depends on a tight mechanical junction or sealant rather than correct sequencing and overlap of materials to produce a watertight joint it's unlikely to archive it, but likely that any leaks at the junction will get worse as the sealant ages.
In addition this design introduces a hole to the roof, which in this case does not appear to closed with sealant. top
Kick out flashings for fiber cement siding
While fiber cement siding products are generally more water
resistant than their wood and "hardboard" counterparts
they are still subject to water damage and it's important
that they be installed in accordance with the manufacture's
instructions. For example the instructions below for James Hardi's
"Hardiplank" siding material (above) specifically
address the requirement for kick out flashings when their fiber
cement siding meets a roof at a roof wall interface such as a
dormer or bay.
As illustrated at left fiber cement siding at a roof/wall intersection is especially
prone to water damage if it has been incorrectly installed, damaged during installation,
is improperly sealed, or is subject to frequent freeze-thaw
cycles.
in this example the siding installation is incorrect in several
respects: in addition to the missing kick out flashing there is
insufficient separation ("holdback") between the siding
and the roof surface and a downspout depositing substantial
additional water on the roof adjacent to the roof-wall junction.
Additional contributing factors may have included incorrect or
insufficient flashings at the corner and failure to properly seal
the field-cut edge.
Such installation details are critical to long term performance,
and even a material as water resistant as fiber cement siding is
prone to water damage under such conditions. top
Preformed
("factory made") kick out flashings
In many applications it is possible to use preformed kick out
flashings, which avoid the need to shop or field fabricate
watertight seams:
Preformed kick out flashings can be designed to direct water
onto a flat surface (left) or with a "scoop" profile to
direct water into a gutter (right). top
Shop made
kick out flashings
Kick out flashing can also be shop or field fabricated, usually from sheet
metal.
Where possible it is usually considered desirable to create the bend by
folding a continuous piece of metal rather than by attempting to create a
watertight junction between two pieces of metal with sealant.
The ideal angel of the arm is determined by the pitch of the roof.
This diagram is an example only, the exact detailing required
will depend on the type of wall cladding, the manufacture's
installation instructions, the other roof and wall flashing
details and local practice and local codes. top
________________________________________________________________________________________________
This page was written for Paragon Property Service Inc.,
Evanston IL by Michael Thomas. I am always interested in
reader's comments about all aspects of real estate
inspection. If you have questions or comments about this article
please feel free to contact me by e-mail or at 847-475-5668.
Rev 1.02 April 8, 2008 08:53
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