Water Around the Chimney? Fixing the Flashing Leak on a Grand Junction Roof
On most homes, the chimney is the single largest hole ever cut through the roof deck. Shingles cover the open field just fine, but that big square opening depends entirely on thin metal called flashing to keep water out. When a roof leaks, the chimney is one of the first places an experienced roofer looks, and around Grand Junction that’s especially true after our summer storms and dry high-desert stretches take turns working on the sealant.
If you’ve spotted a water stain on a ceiling near the fireplace, or damp drywall on the wall the chimney runs through, the flashing is a prime suspect. Here’s how a chimney flashing repair actually comes together, one step at a time, so you know what a crew is doing up there and why.
Why Chimneys Leak Here in Particular
Grand Valley weather is hard on the joint where masonry meets roofing. Summer hail and wind-driven rain push water sideways against the chimney, and months of intense high-desert sun bake the caulk and sealant until it dries, shrinks, and cracks. Once that seal fails, water finds the gap between the brick and the shingles.
The other issue is that chimney flashing is not one piece. It’s a system: base flashing at the front, step flashing up the sides, counterflashing tucked into the mortar, and sometimes a small peak called a cricket behind the chimney to divert water. Any one of those failing can let water in, which is why a proper repair means checking all of them, not just squeezing more caulk on the obvious crack.
Step 1: Confirm the Chimney Is Really the Source
Water travels. A stain that shows up six feet from the chimney can still start at the chimney, running down the deck before it drips. The roofer’s first job is confirming the source rather than guessing.
They’ll usually look inside the attic during or just after a rain, tracing the wet path back uphill to where it enters. Say a homeowner notices a brown ring on the ceiling every time it storms but nothing in between. That pattern points to flashing that only leaks under wind-driven rain, a classic Western Slope symptom. If you want help sorting whether it’s the chimney or something else, you can get matched with a local roofer for a free inspection who checks the whole roof, not just the spot you noticed.
Step 2: Get Up Close and Check the Whole System
Next comes a hands-on look at the chimney from the roof. The crew checks whether the counterflashing is still seated in the mortar joint, whether the step flashing is corroded or lifting, and whether the sealant has pulled away. They’re also looking at the surrounding shingles, because a chimney repair often uncovers other tired spots worth handling at the same time, like the small fixes covered in the fall repairs worth knocking out now.
This is also where they decide the scope. A minor fix might mean re-sealing and re-seating existing metal. A real repair usually means replacing the flashing entirely, which is more work but lasts far longer than another bead of caulk.
Step 3: Remove the Old Flashing and Shingles
With a full flashing replacement, the crew carefully lifts the shingles around the chimney and pulls the old step and base flashing. The counterflashing, which sits in a groove cut into the mortar, gets removed or freed so new metal can slide behind it.
This part looks alarming from the ground because the chimney base is suddenly exposed, but it’s normal. The roofer is clearing everything back to clean decking so the new flashing seats properly. If the deck underneath is soft or rotted, they’ll note it here, since water sitting under failed flashing can quietly damage the wood over time.
Step 4: Install New Step and Base Flashing
Now the layering begins, and layering is the whole secret to flashing that works. The roofer installs base flashing across the front of the chimney, then step flashing up each side. Each piece of step flashing tucks under the shingle above it and over the one below, so water is always directed onto a shingle and never behind one.
A realistic example: on a chimney about three feet wide, a crew might set six or eight individual step flashing pieces up each side, one per shingle course. It’s slow, deliberate work, and it’s what separates a lasting repair from a quick smear of sealant that fails again by next storm season.
Step 5: Set the Counterflashing and Seal
The final metal piece is counterflashing, which tucks into the mortar joint and laps down over the top of the step flashing. This overlap is what keeps water from getting behind the flashing at the brick line. The roofer seats it into the joint and seals that line with a durable, roof-grade sealant, not the hardware-store caulk that dries out in a season or two.
Where the roof design allows, they may also confirm the chimney has a cricket behind it to shed water. Without one, a wide chimney can trap debris and water on its uphill side.
Step 6: Reshingle, Clean Up, and Water-Test
The shingles come back over the new flashing, sealed and fastened. A careful crew often runs water over the finished chimney with a hose to confirm the repair holds before they call it done. Then they clean up nails and debris, the same attention to detail you’d want on any repair, including small ones like the loose ridge cap shingles homeowners often miss.
September is a smart month to handle this. Getting the chimney sealed now means it’s ready before the wetter, colder stretch ahead. Homeowners across Grand Junction and the surrounding Grand Valley tend to get quicker scheduling in early fall than in the spring rush.
Frequently Asked Questions
How do I know if it’s the flashing and not the chimney bricks?
Both can leak, and sometimes both at once. Flashing leaks usually show up as stains where the chimney meets the roof or the wall below it. Cracked masonry or a missing chimney cap can also let water in from the top. A roofer checking the chimney will look at the flashing, the mortar joints, and the cap together, since fixing one and ignoring the other just moves the problem.
Can’t I just add more caulk to the cracked seal myself?
Fresh sealant might slow a leak briefly, but it rarely fixes the real problem, which is usually failed or poorly layered flashing underneath. Caulk on top of bad flashing is a patch on a patch, and the leak tends to return. It’s also risky work at height. If the flashing itself has failed, the lasting fix is replacing the metal.
What does a chimney flashing repair usually cost?
It depends on the chimney size, how much flashing needs replacing, and whether there’s hidden deck damage. It’s generally a targeted repair rather than a full roof job, but the range varies. Our guide to what roof repair costs in Grand Junction gives realistic figures, and if the roof is aging overall, comparing against a full replacement cost can help you decide whether to repair or plan ahead.