Ladue has a lot of stone. Many of the older houses along its winding streets carry a stone face on the front elevation, and where that face meets a roof, a gable, a dormer, or a porch, the water has to be stopped by metal that sits inside the stone, not on top of it. A roof estimate that says "flash the wall" without naming the metal, the depth, and the joint it sits in has left the most likely leak point undefined.
Why the stone line is a different detail
A wood-sided wall takes step flashing that is tucked under the siding and lapped over the shingles, and most roofers can describe that from memory. Stone is heavier and stiffer, and it moves on a different schedule. A veneer wall rests on a steel shelf angle or a lintel at the openings, and the roof framing that bears against it settles on its own timeline. When the stone and the roof are not moving together, the joint between them opens over the years, and the first sign is usually a stain on the ceiling below the wall, not a mark on the stone.
The freeze and thaw cycle in St. Louis adds to this. Water gets into the mortar joints during a wet March, freezes, and pushes the joint apart a little each winter. Ice damming at the eave can back water up under the first course of shingles, and that water runs along the top of the stone wall until it finds the nearest gap. The roof surface may look sound from the driveway the whole time.
Ladue owners often ask whether new metal will show. Counterflashing in a matching finish, set into a re-pointed joint, usually reads as part of the mortar line from the driveway. A bright metal piece pressed onto the face of the stone reads as a patch. Ask to see a sample of the finish and the mortar color before the crew cuts anything.
What the flashing should do
Where a sloped roof runs into a vertical stone wall, the standard detail is step flashing set in each course of shingles, with the vertical leg rising up the stone and ending behind a counterflashing. The counterflashing is the piece that matters most on stone. It should be set into a groove cut in the mortar joint, called a reglet, or into a joint that has been opened and re-pointed for the purpose. It then laps down over the step flashing, so the water is shed outward onto the shingles and not into the mortar.
Surface caulk is not the same thing. A bead of sealant on the face of the stone may look tidy and will fail within a few seasons under the sun and the freeze. A quote that says "caulk the stone line" has described a repair, and a repair is not the same as a flashing system. Ask whether the counterflashing is going into the stone, what depth the groove will be, and what mortar will fill the re-pointed joint.
At the bottom of the roof where it meets the wall, a kick-out flashing usually belongs there, so water coming down the wall is turned away from the siding or the back edge of the gutter. On a stone face that drops into a gutter, the kick-out is the piece that stops the stream from running down the stone and into the mortar below the eave.
Where the stone meets the roof on a Ladue house
Ladue houses tend to have more of these junctions than a typical subdivision home. A front gable with a stone face, a dormer on a stone wall, a porch roof tying into a stone column, and a chimney rising beside a stone-faced gable can all sit within a few feet of each other. Each one needs its own line in the scope. A roofer who walks the front elevation once and writes "flash all walls" has not priced four separate details.
Stone also carries the roof load differently. A stone-faced gable may have a short wall that stops below the ridge, and the top of that wall needs a cap that sheds water to both sides. If the cap is missing or cracked, rain runs into the top of the wall and through the joints below the roof line. That is a masonry repair, and it belongs in the roof conversation, because the flashing cannot seal a wall that is leaking from its top.
What it costs
Stone-line flashing is usually priced by the linear foot of the junction, plus the labor to cut the reglet and re-point the joint, plus the counterflashing metal. The number moves with the amount of stone, the number of openings, and whether the mortar is sound enough to cut into. If a roofer has to repoint a long run before the counterflashing will seat, that repointing should be a line in the quote, not something discovered on the second day of the job.
Ask each roofer to show the stone junction as its own line, with the linear footage, the metal gauge, and the finish. Ask whether the price includes repointing where the groove is cut, and whether the mortar match is part of the price. A single lump sum that covers "flashing and sealing" can make one bid look cheaper than another when the lower one has left out the masonry.
What to ask
Before you pick a roofer for a stone-faced house, ask these questions and get the answers in writing.
- Where will the counterflashing go: into a cut reglet, into a re-pointed joint, or onto the face of the stone?
- How deep will the groove be, and what mortar will fill the joint after the metal is set?
- Which walls and gables on my house are being treated as stone junctions, and how many linear feet is each?
- Is repointing included, and if the mortar is not sound, what is the price per foot to repoint before the flashing goes in?
- Is there a cap on top of any stone wall, and is it being replaced or only inspected?
- What metal and gauge is the counterflashing, and does it match the step flashing and drip edge in the quote?
- Will the crew photograph each junction before the metal covers it, so the file shows the groove and its depth?
Keys Roofing documents each stone junction with dated photographs and writes the scope with measurements, so the homeowner holds the same record the crew works from. If you want the stone line walked before you decide, call the office at (314) 220-2333 and ask for the junction list to be part of the estimate visit.