If your chimney leaks when it rains, the most likely culprit is the flashing, the metal seam between your chimney and roof. That makes it a repair, not a replacement, and repairing it is a specialty of ours.
Flashing: where good roofs leak
Shingles almost never fail in the open field. Roofs leak at the transitions, everywhere two surfaces meet and metal has to carry the water: chimneys, walls, valleys, skylights, pipes. That metal system is flashing, and it’s both the most failure-prone part of a roof and the part most often botched, because doing it right is fussy metalwork and doing it wrong is a caulk gun and ten minutes.
Around Dane County, flashing takes extra abuse: ice dams pry at it every February, freeze-thaw cycles work its fasteners loose, and the mortar joints holding counter flashing erode a little more each winter. A flashing detail that lasts decades in Tennessee gives up early here.
What we repair
Chimney flashing is the classic. We rebuild both layers properly: step flashing woven into the shingles, counter flashing cut into the mortar joint (not surface-glued to the brick) and folded over it. If the mortar joints themselves are crumbling, we’ll show you photos and tell you whether a mason should see it first.
Wall and dormer flashing matters where a roof meets siding. Water sneaks behind cladding and shows up as mystery stains a floor below. Same weave, same discipline.
Valley flashing works hard: valleys carry more water than any other line on your roof, and ice sits in them longest. Rusted-through or nail-punctured valley metal is a common find on 20-year-old roofs that are otherwise healthy.
Pipe boots and vent flashing round out the list. The humble rubber pipe boot cracks after 10-15 Wisconsin summers, and it’s the single most common leak source we see. A boot swap is quick and cheap, which is exactly why replacement-focused companies don’t want the call. We do.
Repair honesty, as always
Flashing repair is usually the textbook case for repairing: the fix is targeted, permanent, and a fraction of replacement cost. But if your shingles are at end-of-life, we’ll tell you, because new flashing on a dying roof gets torn off with everything else in three years. That’s money wasted. The repair-vs-replace guide covers how we make that call. Not sure the chimney is even the source? Why is my roof leaking walks through it, or book a full inspection and get every detail checked at once.
We repair flashing across Sun Prairie, Madison (where whole neighborhoods of older brick-chimney homes hit flashing age together), Waunakee, and the rest of Dane County. Get in touch with a photo of your chimney if you have one; it often tells us half the story before we arrive.
Frequently asked questions
How much does chimney flashing repair cost?
Far less than the replacement quote a chimney leak usually triggers. Re-sealing or repairing a section is modest work; even a full re-flash (new step and counter flashing, properly cut into the mortar joints) remains a small fraction of a roof replacement. Firm price after we look at it, before we start.
Why does my chimney leak when it rains?
Nine times out of ten it is the flashing system: step flashing that has rusted or pulled loose, counter flashing that has separated from the mortar joint, or a failed bead of old sealant someone used as a shortcut years ago. The brick and the shingles are usually both fine. The seam between them is the problem.
What is the difference between step flashing and counter flashing?
Step flashing is the row of L-shaped metal pieces woven into the shingles against the chimney or wall, carrying water down the roof one shingle at a time. Counter flashing is the upper layer, cut into the chimney's mortar joints and folded down over the step flashing so water cannot get behind it. Both layers have to be right, because one without the other eventually leaks.
Can flashing be repaired without redoing the roof?
Yes. Flashing is repaired and replaced independently of the shingle field all the time. It is one of the most common repairs we do, and one of the clearest cases where a targeted fix beats a replacement pitch. The exception is a roof at the end of its life, where new flashing would outlast everything around it.
Is roofing cement or caulk an acceptable flashing fix?
As a permanent fix, no. A tube of sealant smeared over failed flashing buys months, then traps water behind the patch and makes the eventual repair bigger. Real flashing repair is metalwork: cutting, bending, and layering so gravity does the sealing. Sealant has a place in the system, but it is the gasket, never the structure.