Chimney Flashing Leaks in West Michigan: Why the Metal Fails Before the Brick Does

Published July 20, 2026 by Quality Roof Repair Grand Rapids

A brown stain spreading on the ceiling next to the fireplace is one of the most common calls our team takes, and the homeowner almost always assumes the chimney itself is the problem. Cracked brick, bad crown, something expensive. Sometimes, sure. But most of the time the masonry is fine and the metal where the roof meets the chimney has given up. That joint is the hardest-working intersection on the whole roof, and in West Michigan it takes freeze-thaw, lake-effect snow, and wind-driven rain from every direction. Here is how the flashing system works, the ways it fails, and what fixing it actually involves.

The Two-Part System: Step Flashing and Counterflashing

A chimney passing through a roof creates four joints that water attacks constantly. Shingles alone cannot seal them, so the joint gets metal, and the metal comes in two layers that work together.

Step flashing is the first layer. Along each side of the chimney, an L-shaped piece of metal goes under every course of shingles, one leg on the roof deck, one leg up the chimney side. Each piece overlaps the one below it like the shingles themselves, stepping up the slope. Water coming down the roof hits metal, not the seam, and keeps moving.

Counterflashing is the second layer, and it is the one most homeowners have never heard of. The top edge of step flashing sits against the brick, and water running down the chimney face would sneak behind it. So a second set of metal is cut into the chimney's mortar joints, sealed, and lapped down over the step flashing. Water off the brick lands on the counterflashing, sheds onto the step flashing, and rides out onto the shingles. The low side of the chimney gets an apron flashing, and the high side gets either a back pan or, on wider chimneys, a cricket.

When the system is right, every path water can take ends on metal that drains downhill. When any piece fails, water finds the framing, and the stain shows up a few feet from the chimney where nobody thinks to look. That offset is exactly why chimney leaks get misdiagnosed, something we covered in our guide to finding where a roof leak actually starts.

How Chimney Flashing Fails in West Michigan

The counterflashing pulls out of the mortar

Counterflashing is only as good as the mortar joint holding it. Our freeze-thaw cycles, 40 to 60 of them in a typical winter by the National Weather Service Grand Rapids office's counts, work the metal loose a little at a time. Once the reglet joint opens, the counterflashing flops away from the brick and water runs straight down behind the step flashing. If the mortar joints themselves are crumbling, the fix involves the mason as well as the roofer.

Sealant reaches the end of its life

The counterflashing joint is sealed, and no sealant lives forever on a chimney that bakes in July and freezes in January. Ten years is a good run. Past that, the bead cracks, curls, and lets water into the reglet. This is the cheapest failure to fix and the easiest to catch early, which is why the chimney joint belongs on any roof inspection checklist.

Rust eats the metal

Older galvanized flashing rusts from the underside out, and by the time orange streaks show on the shingles the metal is thin. Rusted-through step flashing cannot be patched piece by piece in place; the affected shingle courses come up and the flashing gets replaced.

Wide chimneys with no cricket

The high side of a wide chimney is a dam. Snow piles against it, water pools behind it, and eventually it finds a way in. The residential code, Michigan's included, requires a cricket, a small peaked diverter, when the chimney runs wider than 30 inches parallel to the ridge and does not intersect it, per IRC R1003.20. Plenty of older West Michigan homes with broad brick chimneys never got one. Every winter, snow sits against those chimneys for weeks, and the back pan is the first thing to give.

The previous repair was a tar job

We see it weekly: flashing smeared over with roofing cement, sometimes in layers from repeated attempts. Tar over failed flashing is a one-season patch that makes the eventual proper repair harder. It also tells you the leak has been active for years, so the decking behind it deserves a look.

What a Proper Repair Involves

The right fix depends on which layer failed. Re-sealing sound counterflashing is quick. Re-seating counterflashing means grinding the reglet joint clean, bedding new metal, and sealing it. Replacing step flashing means lifting the shingle courses along the chimney and weaving in new metal piece by piece. A missing cricket means building one: framing, sheathing, ice-and-water membrane, flashing, and shingles to match. On cost, 2026 national figures put a reseal at a couple hundred dollars and full flashing replacement at roughly $325 to $1,400 depending on chimney size, pitch, and metal. That is cheap insurance against what the same water does to framing and drywall if it runs another two winters.

One more West Michigan note: if the mortar joints are soft enough that the counterflashing will not hold, the chimney needs tuckpointing before new metal goes in. We fold that into the same project when it comes up, and the difference between a repair-sized bill and a rebuild-sized one is usually how early the problem got caught. Our roof repair service treats the chimney joint as part of the roof, not someone else's problem, and our Michigan roof repair cost guide covers where flashing work fits in the bigger pricing picture.

When to Get It Looked At

Any ceiling stain within a few feet of the chimney, damp brick in the attic after a soaking rain, visible rust streaks, peeling sealant, or daylight at the counterflashing line is reason enough. So is buying a house with a tarred-over chimney joint. The inspection takes minutes, the early fix is the cheap one, and fall is the right deadline: whatever is loose now, lake-effect snow will find in January.

Frequently Asked Questions

How do I know if my chimney flashing is leaking?

The usual signs are water stains on the ceiling or wall within a few feet of the chimney, damp brick or drywall in the attic around the chimney chase after rain, rust streaks on the flashing itself, or dried sealant peeling off the metal. Leaks show up during long soaking rains and snowmelt more than short summer storms.

What is the difference between step flashing and counterflashing?

Step flashing is the row of L-shaped metal pieces woven into each shingle course where the roof meets the chimney side, carrying water down the slope. Counterflashing is the second layer, embedded into the chimney's mortar joints and lapped down over the step flashing, so water running down the brick face never gets behind the metal.

How much does chimney flashing repair cost in 2026?

National 2026 figures put resealing at a couple hundred dollars and a full flashing replacement at roughly $325 to $1,400 depending on chimney size, roof pitch, and material, with typical single-flue jobs landing near the middle. Copper costs more than aluminum or steel. Mortar repairs to accept new counterflashing add to the bill.

What is a chimney cricket and does my chimney need one?

A cricket is a small peaked diverter built on the high side of the chimney that splits water and snow around it instead of letting them pile against the brick. The residential code requires one when the chimney is wider than 30 inches parallel to the ridge and does not sit on the ridgeline. Wide chimneys without crickets are a leak we see over and over.

Can I just caulk leaking chimney flashing?

Sealant is a patch, not a fix. A bead of the right sealant can buy a season on a small gap, but caulk over failed step flashing or pulled-out counterflashing traps water more often than it stops it. Tar smeared across flashing is the classic sign of a leak that kept coming back. Proper repair means re-seating or replacing the metal.