Chimney Flashing Leaks: Why They Happen and How to Fix Them for Good

Every time it rains hard, you see it. Water stain on the ceiling. Right next to the chimney.

Your roofer came out twice. "Fixed" it both times. Still leaks.

Here's why chimney flashing is the most common leak source we see in Richmond — and what actually stops it permanently.

What Chimney Flashing Does

Flashing is the metal barrier between your chimney (brick or stone) and your roof (shingles). Without it, water runs down the chimney, hits the roof, and flows straight into your attic.

Two types work together:

Step flashing: L-shaped metal pieces that run up the sides of the chimney, woven between the shingle courses. Each shingle overlaps one piece of step flashing.

Counter flashing (or cap flashing): Separate metal pieces embedded into the chimney mortar joints. These fold down over the step flashing to keep water from getting behind it.

When both are installed correctly, water hits the chimney, runs down onto the counter flashing, drains onto the step flashing, and flows out onto the shingles. No leaks.

When either fails, water finds a way in. Always.

Why Chimney Flashing Fails

Poor Initial Installation

This is the big one. Most chimney leaks aren't from age. They're from corners cut during the original installation or last roof replacement.

Common mistakes we fix:

No counter flashing at all. Some roofers skip it entirely. They caulk the step flashing to the brick and call it done. Caulk fails in 2-3 years. Then you leak.

Step flashing too short. Code requires at least 4" of step flashing running up the chimney and 4" under the shingles. We've seen 2" pieces. Water jumps right over them.

Not enough pieces. Step flashing should be installed with every shingle course (roughly every 5-6 inches vertically). Cheap jobs use one piece per two or three courses. Water finds the gaps.

Caulk instead of proper counter flashing. Embedding metal into the mortar joints takes time. Slapping a bead of caulk along the brick takes 30 seconds. Guess which one contractors in a hurry choose.

Failed Caulk or Sealant

If your chimney flashing was installed with caulk as the primary seal, it's already failing or will fail soon.

UV exposure, temperature swings (brick gets hot in summer, cold in winter), and thermal expansion all break down caulk. In Richmond's climate, caulk around chimneys lasts maybe 3-5 years maximum.

Then it cracks. Water gets in.

Deteriorated Mortar Joints

Counter flashing gets embedded in the mortar between bricks. When that mortar deteriorates (which happens over decades), the flashing loosens. Water flows behind it.

Chimneys built before 1980 often have mortar that's crumbling. The flashing might have been perfect when installed, but the chimney itself is failing.

Settled or Leaning Chimney

Chimneys are heavy. If the foundation wasn't built right or the ground has shifted, the chimney can settle or lean slightly.

That pulls the flashing away from the roof surface. Suddenly there's a gap. Water goes in.

We see this most often in homes built on clay soil (common in Henrico and Chesterfield). The ground shifts seasonally, the chimney moves imperceptibly over years, and eventually the flashing separates.

Ice Dams

Water backs up behind an ice dam, gets under the shingles, and finds any weakness in the chimney flashing.

Even good flashing can leak if there's 3 inches of water sitting against it for days during a freeze-thaw cycle.

How We Actually Fix Chimney Flashing

Not with caulk. That's a temporary patch at best.

Full Reflash

This is the right way:

1. Remove shingles around all four sides of the chimney (usually 3-4 courses)
2. Remove old step flashing (if it exists)
3. Install new step flashing — one L-shaped piece for every shingle course, properly sized (minimum 4x4 inches on each leg)
4. Cut slots in mortar joints about 1.5 inches deep
5. Install counter flashing bent to the correct profile, embedded into the mortar slots
6. Fill mortar slots with fresh mortar or polyurethane sealant rated for masonry
7. Reinstall shingles properly overlapping the step flashing
8. Apply ice and water shield at the base if it wasn't there originally

Done right, this lasts as long as your roof. Usually 20-25 years or more.

Cost: $800-1,400 for a typical Richmond chimney (3x3 feet).

Cricket Installation

If your chimney is wider than 30 inches (measured parallel to the roof ridge), code requires a cricket.

A cricket is a small peaked structure built on the upslope side of the chimney. It diverts water around the chimney instead of letting it pool behind it.

Most chimneys in Richmond don't have them. Should they? If the chimney is wide, yes.

We've fixed dozens of leaks simply by adding a cricket that was never there in the first place. Water was pooling behind the chimney, overwhelming the flashing, and leaking through.

Cost to add a cricket: $600-900 depending on chimney size.

Chimney Crown Repair

Sometimes the leak isn't the flashing at all. It's the chimney crown (the concrete cap at the top).

Cracked crowns let water into the chimney structure. It runs down inside the brick, eventually seeping out at the flashing level and dripping into your attic.

You think it's a flashing leak. It's actually a crown leak showing up at the flashing.

If we find crown damage, we'll tell you. Fixing it might cost $400-800 (minor repair) or $1,200-2,000 (full crown rebuild).

What Doesn't Work (But Contractors Keep Trying)

Roof cement (tar). It's a patch, not a fix. Lasts maybe 6-12 months. Then you're calling again.

Caulking over old flashing. Same problem. Temporary at best.

Replacing shingles without addressing flashing. Water doesn't care about your new shingles if the flashing is still broken.

"Sealing" the brick-to-metal joint. There shouldn't need to be a seal there. Proper counter flashing embedded in mortar doesn't rely on sealant.

If a contractor quotes you $200-300 for a chimney leak fix, they're planning to caulk it. That's not a fix. It's kicking the problem down the road.

Richmond-Specific Challenges

Brick chimneys on old homes. Many Richmond chimneys built before 1970 have deteriorating mortar. We often need to coordinate with a mason to repoint the chimney before we can properly flash it.

Prefab metal chimneys. Some Richmond homes (especially ranches built in the 1980s-90s) have metal chimney chases instead of brick. These use different flashing techniques. Storm collars and chase covers often fail before the roof flashing does.

Historic homes in The Fan. These chimneys are often oversized (4x4 feet or larger) and require custom flashing fabrication. Not every roofer has the sheet metal skills for this. We do.

When to Reflash Your Chimney

During any roof replacement. Always. New roof, new flashing. Don't reuse 20-year-old flashing with brand new shingles.

If you see water stains near the chimney. Don't wait for it to get worse. It will.

If caulk is visible around the chimney base. That means someone patched it instead of fixing it.

Every 20-25 years regardless. Even if it's not leaking, flashing degrades over time.

After any chimney repair work. If a mason worked on your chimney, have a roofer inspect the flashing afterward. Masons sometimes disturb it without realizing.

What to Ask Your Contractor

Before hiring someone to fix your chimney flashing:

"Will you install counter flashing or just caulk it?" Only one right answer: counter flashing embedded in mortar.

"How many pieces of step flashing will you use?" Should be one per shingle course, minimum. A 5-foot chimney should have 10-12 pieces per side.

"Do I need a cricket?" If your chimney is wider than 30 inches, probably yes.

"What's the warranty on the flashing work?" We warranty flashing for the life of the roof. Anyone offering less is cutting corners.

"Can you show me photos of a similar job you've completed?" They should have dozens. If they can't, they haven't done many.

The Cost of Getting It Right

Full chimney reflash: $800-1,400 Add a cricket: additional $600-900 Chimney crown repair: $400-2,000 (if needed) Coordinating with mason for repointing: varies, $500-2,500 typically

Patching with caulk: $150-300

The patch fails in a year. You call someone else. They patch it again. You're spending $150-300 every year instead of $1,000 once.

We've replaced flashing on chimneys that had been "repaired" six times in ten years. Total spent on patches: $1,800. Cost to fix it right the first time would've been $950.

Do the math.

What We Actually Do

When you call us for a chimney leak:

1. We inspect from the attic (looking for the water entry point)
2. We inspect from the roof (checking flashing condition, chimney crown, mortar)
3. We tell you exactly what's wrong
4. We quote you for the proper fix, not a temporary patch
5. We show you photos of what we find

If you want the temporary patch to get through the next few months, we'll do that. But we'll tell you it's temporary.

Most people choose the permanent fix once they understand the options.

Call (804) 238-7837 or request an inspection if your chimney's been leaking and nobody's been able to fix it. We'll show you why and fix it for good.

One More Thing

If your chimney hasn't been used in years (no fireplace, old furnace flue that's been capped), consider having it removed entirely.

Sounds drastic. But removing an unused chimney eliminates the most common leak point on your roof, saves you $1,000+ in flashing costs every roof replacement, and opens up usable attic space.

We've removed 8 chimneys in Richmond in the past two years. Every homeowner said the same thing afterward: "We should've done this years ago."

Just something to consider.