If your house is a split-level, or the roof steps down from the main section to a lower wing, there is a place where the upper roof meets a wall that rises above the lower roof. That wall is the step. It is the seam where two roof planes end against a vertical face, and it is the detail many roof quotes in older Creve Coeur neighborhoods fold into a single shingle line. The step rarely fails first in the shingles. It fails at the flashing, and the flashing is the part a homeowner needs to be able to point to on paper.
Why the step is separate work
On a plain gable, the shingles run straight from eave to ridge, and the only flashing at the edges is the drip edge, the rake, and any valleys. On a stepped roof, the upper slope ends against a wall that continues above the lower roof. Water running down the upper slope has to be carried over the lower roof and kept away from the wall. The usual method is step flashing, a series of short L-shaped metal pieces woven into the courses of shingles, one piece per course, each lapped over the one below it. Where the wall is masonry, a counterflashing is set into the mortar joint above and bent down over the step flashing. Where the wall is siding, the siding and the flashing have to be sequenced so water runs over the flashing and never behind it.
The work is slow for a reason. Each piece has to be cut to the pitch and laid in the right order, and the crew has to lift the course above it to set it properly. A crew that strips the upper slope in one morning and then tries to weave the step in the afternoon is usually rushing the part that matters most. This is one reason the step belongs in the written scope as a count of steps and a run of linear feet along the wall, not as a phrase buried in the shingle line.
Where the water goes at the step
Two things work against a step in this region. The first is ordinary rain, which runs down the upper slope with every storm. The second is freeze and thaw. St. Louis winters pass through many freeze and thaw cycles in a season, and each cycle pushes meltwater into any small gap at a joint. When snow sits on the lower roof and the upper roof sheds onto it, the lower roof edge can build an ice dam, and the water trapped behind that dam can climb back up under the step. A step flashed correctly still depends on the lower roof edge shedding water, which is why the ice and water shield question and the eave detail belong in the same conversation as the step.
Water also gets in through the wall itself. If the step flashing is set on top of the siding instead of under it, or the siding was never cut back to let the flashing sit properly, water runs behind the flashing and along the sheathing. The first sign is often a stain on an interior wall or ceiling near the corner of the lower roof. That stain does not always sit directly beneath the point of entry, because water tracks along framing before it shows, so the stain is a clue to check the step, not a measurement of where the step failed.
Town roofing: what Creve Coeur homeowners should check
Creve Coeur has a mix of older houses and newer builds, and the stepped detail shows up often on split-levels and on additions tied into a main roof. If your house has an addition with a lower roof, a step is probably there even if you have never looked at it. Walk the outside of the house and look for any place where one roof surface ends against a wall that keeps going above it. Photograph it from the driveway, from the lower roof edge if it is safe to stand there, and from the attic if you can reach the wall plate.
Then check with the city. Creve Coeur issues its own building permits, and a re-roof that changes flashing at a wall may need a permit or an inspection, depending on the scope of the work. Call the city's building division before you set a start date, not after the crew arrives. A permit timeline can move the date, and a crew that has already ordered shingles for a Monday start will want to know that before the bundles are delivered.
What it costs
A step is priced as part of the roof, but it should show up as its own line. The quote should state how many steps there are, how many linear feet of wall the step covers, and what flashing material is being used. Counterflashing at masonry is often quoted differently from step flashing at siding, so the two should not be merged into one allowance. If a quote gives a lump sum for flashing with no count attached, you cannot compare it fairly to another quote that lists the steps.
Do not expect the step to be a small number on a stepped roof. It is labor-heavy compared with the open field of the shingles, because the crew works the detail by hand, one piece at a time. A low figure for the step often means the step was not measured at all, or that the work was assumed to be a simple lap. Ask each roofer how many steps they counted and whether they counted from a drawing, from a ladder visit, or from photographs. The answer tells you whether the number was measured or guessed.
What to ask
Put these questions to each roofer in writing before you choose:
- How many step flashing pieces does your scope include, and on which walls are they?
- Is the step flashing from the upper roof to the wall listed separately from any counterflashing at masonry?
- Will the siding be cut back so the flashing sits under it, or will the flashing be set on top of it?
- Is ice and water shield included at the lower roof edge and under the step?
- Does your crew set the step flashing by hand, one piece per course, or does the scope use a prefabricated kit?
- Who pulls the Creve Coeur permit, and does the scope include a re-inspection after the step is closed?
- What photos will you send of the step before the wall is covered?
Keys documents the step with photographs and measurements and puts the written scope, with those numbers, in your hands before the work starts. If you want to walk the step with someone before you decide, call the office at (314) 220-2333.