Most of the serious water damage we find on Milwaukee houses is not in the middle of a roof or the middle of a wall. It is at the seam between them, on details that belong to neither trade cleanly, which is exactly why they get missed.
The Junction Nobody Owns
When a porch roof, a garage roof, or a dormer dies into a wall, the waterproofing there is a layered assembly. Step flashing goes in shingle by shingle, each piece lapped over the one below and tucked up behind the siding. At the bottom of that run, where the roof edge meets the gutter, a kickout diverts water outward.
That assembly is half roofing and half siding. A roofer who is not touching the wall will often flash to the existing siding and leave it. A siding crew who is not touching the roof will cut around what is already there. Both can hand you finished-looking work with a gap in the middle of it.
We open these walls up regularly. The pattern is consistent: step flashing that stops short, no kickout, and a column of black sheathing running from that point straight down to the sill plate.
What Correct Looks Like
- Step flashing woven into each shingle course, not one continuous bent piece of metal run up the wall. Continuous flashing at a sloped junction fails, because there is no way to lap it with the shingles.
- A kickout at the bottom of every roof-to-wall run, angled to throw water into the gutter.
- House wrap lapped over the vertical leg of the step flashing, so water on the drainage plane runs out on top of the metal rather than behind it.
- Counterflashing at masonry, cut into a mortar joint rather than surface-sealed with caulk. Caulk at a brick-to-roof junction is a two-year solution presented as a permanent one.
- Two inches of clearance between siding and roof surface. Siding run tight to shingles wicks water and holds snow against the wall.
Why the Sequencing Matters
Doing both at once is not an upsell, it is the only way some of these details get built correctly. House wrap has to lap over flashing that is installed with the roof. If the roof goes on first and the siding comes off two years later, someone has to decide whether to disturb the flashing or work around it. Working around it is what usually happens.
If the two jobs genuinely cannot happen together, sequence roof first, and make sure the roofer leaves the step flashing long and proud so the siding crew can lap the wrap over it properly. Tell both contractors that is the plan. It costs nothing and it prevents the most common failure mode we see.
The Ice Dam Connection
Roof-to-wall junctions are where ice dams do their most expensive work. Water backing up behind an ice dam does not just get under shingles, it finds the wall junction and runs down inside the siding. Houses with chronic ice dam problems and no kickout flashing tend to have wall rot as well as ceiling stains, and the wall damage is the part nobody discovers until later.
If you are dealing with ice dams, the fix is attic air sealing, insulation, and ventilation. But while the work is happening, get the wall junctions inspected too.
What to Ask For
Whether you are hiring one contractor or two, ask specifically: is kickout flashing included, is step flashing being replaced rather than reused, and how does the house wrap lap over it. Reused step flashing is a common shortcut. The old metal has nail holes in the wrong places and has usually lost its shape.
We do roofing, siding, and gutters with our own crew, largely because these junctions are where jobs go wrong when nobody owns the whole detail.
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