Flashing Pulling Away from the Chimney
What’s Happening
Flashing that’s pulling away from your chimney is almost always a failed seal between the metal flashing and the masonry – mortar has crumbled, caulk has dried out, or the flashing itself has lifted. Water is either already getting in or has a clear path to do so the next time it rains. This needs attention soon, not someday.
Chimney flashing sits at one of the hardest junctions on any roof: metal meets masonry, two materials that expand and contract at different rates every time the temperature swings. Over years, that constant movement breaks the seal. Once it goes, water follows the gap straight down into the roof deck, the framing, and sometimes the ceiling below – often without leaving any visible stain until the damage is already serious. The good news is that a flashing repair, caught before the deck is compromised, is one of the more straightforward fixes on a roof.
Why It Happens
Mortar Joint Failure
The top edge of step flashing and counter-flashing is often tucked into a mortar joint that’s been raked out and sealed. Mortar is porous and brittle, and after enough freeze-thaw cycles it crumbles. When it goes, the flashing loses its anchor and begins to pull away from the chimney face. You can usually see this from the ground: white powder streaking the brick below the flashing line, or a visible gap between the metal and the chimney where there used to be none.
Caulk or Sealant Dried Out and Cracked
Some installations rely on a flexible sealant rather than mortar as the primary seal at the flashing edge. Caulk has a shorter service life than most homeowners expect – heat, UV exposure, and seasonal movement dry it out and crack it, sometimes within five to ten years on a south-facing chimney. If you can see a thin, cracked bead of old caulk around the flashing edge with visible gaps, this is likely the cause. The flashing itself may still be in good shape; the seal around it is not.
Flashing Nails or Anchors Have Backed Out
Step flashing is nailed to the roof deck and sometimes screwed or clipped to the chimney. Fasteners back out over time from thermal movement, and once they do, the flashing can lift at the corners or along one side. You might notice this as a section of flashing that’s visibly raised or slightly buckled rather than lying flat. In some cases you can hear it: a soft metallic ticking during temperature swings in the morning or late afternoon.
The Flashing Has Reached the End of Its Life
Aluminum flashing typically lasts fifteen to twenty years; galvanized steel can go longer but will eventually rust through at the edges or at any point where a fastener hole has opened up. If the metal itself is pitted, rusted, or has developed small holes, no amount of resealing will fix it – the flashing needs to be replaced. Look for orange-brown staining on the shingles or brickwork below the flashing, which is rust running down from corroded metal above.
What to Do Right Now
- Photograph the gap from the ground using your phone’s zoom. Get a clear shot of where the flashing meets the chimney on each face – front, back, and both sides. These photos are exactly what your local Ridgeline Roofing Co. team will want to see when you call, and they’ll help the technician arrive prepared.
- Check your attic if you can safely access it. Look along the interior framing near the chimney for dark staining, soft wood, or any sign of moisture. Do this from the attic floor – do not climb onto or lean against roof framing. If you see standing water or heavy staining, note it for the technician.
- Do not attempt to reseal or caulk the flashing yourself while it’s pulling away. A gap this size needs the flashing properly reseated before any sealant is applied. Caulking over a lifted flashing edge traps moisture behind it and often makes the underlying problem worse.
- Stay off the roof. Roof work near a chimney involves working at height on an angled surface, often with deteriorated materials underfoot. This is a job for a uniformed, background-checked technician with the right equipment – not a ladder and a caulk gun.
- If rain is in the forecast within the next day or two, call now. A failing flashing seal can turn a small repair into a damaged roof deck and compromised framing in a single hard rain. A live person at Ridgeline answers every call, around the clock, including nights and weekends: (844) 563-1816.
How We Fix It
When your local Ridgeline Roofing Co. team arrives, the technician goes up on the roof – not the driveway – and documents the flashing condition with photos before touching anything. You’ll see what we see.
From there, the repair path depends on what’s failed. If the mortar joint has crumbled, we rake it clean, reset the counter-flashing, and repoint with the right material for masonry. If the sealant has given out but the flashing is sound, we clean and re-seal the edge properly – not just a bead over the top of the old caulk. If the flashing itself has corroded or lifted beyond reseating, we remove it and install new step and counter-flashing sized for your chimney and matched to your roofing system. We work with GAF, CertainTeed, Owens Corning, and the other manufacturer lines we’re authorized to install, so the materials are right for the job.
Most chimney flashing repairs are completed in a single visit. Before any work starts, you get a written estimate – that number is the number on the invoice, no surprises. Every repair is backed by our 90-Day Done Right Promise: written, no arguing, no paperwork. If it’s not right, we come back and make it right. This falls under our Roof Repair service, and in cases where the flashing failure has allowed water into the deck or framing, our team will assess whether Roof Replacement and Installation work is needed as part of the same visit.
Frequently Asked Questions
It can’t wait safely, especially if rain is coming. A gap in chimney flashing is an open path for water into the roof deck and framing – damage that starts small and compounds quickly. Wet framing can lead to rot, mold, and structural repair costs that far exceed what the flashing fix would have been. Call (844) 563-1816 and we’ll help you figure out how urgent your specific situation is.
A live person answers our phones 24 hours a day, seven days a week – including nights, weekends, and during storms. Your local Ridgeline Roofing Co. team will work to get a technician to you as quickly as schedules allow, and if you’ve got water coming in right now, tell us that when you call. Reach us at (844) 563-1816.
It depends on what’s failed. If just the sealant or the mortar joint has given out but the metal is still sound, a repair is often the right answer. If the flashing is corroded, cracked, or badly lifted, replacement is the better long-term move. Our technician will tell you which it is – with photos from your actual roof – and put the price in writing before anything starts.
It depends on the cause. Storm damage to flashing – from wind, hail, or falling debris – is often covered under a standard homeowner’s policy. Gradual wear or deferred maintenance typically is not. When there’s a legitimate storm-damage case, your local Ridgeline team can document the damage with photos and walk you through what the insurer will likely want to see. We don’t chase claims – we just make sure you have what you need to make yours accurately.
Get It Fixed
Call (844) 563-1816 – a live person answers right now, day or night. Your local Ridgeline Roofing Co. team will schedule an inspection, go up on the roof, show you what they find, and give you a written estimate before a single nail moves. No surprises on the bill. No runaround if something’s not right.
Written by Pete Navarro, Owner at Ridgeline Roofing Co., serving homeowners across the country since 1984.