Chimney Flashing & Leak Repair
A chimney that only leaks when it rains almost always has one culprit: failed flashing. Union Roofing repairs and replaces chimney flashing across Philadelphia, sealing the most common leak point on any roof — before the water reaches your ceilings and framing.
The chimney is one of the trickiest spots on any roof — it’s a large object punching through the roof plane, and the only thing keeping water out at that junction is the flashing. Over time, flashing corrodes, sealant dries and cracks, and mortar joints deteriorate, letting water slip in exactly where the roof meets the masonry. Because the water often travels before it appears, a “chimney leak” can show up as a stain several feet away. Union Roofing traces the leak to its true source and rebuilds the flashing system so it stays watertight.
Why Chimneys Leak
A handful of failures cause almost every chimney leak we’re called to fix.
The #1 cause. Step flashing, counter-flashing and the base seal corrode or pull loose, opening a path for water.
Old caulk and roofing cement dry out and split, breaking the seal around the flashing edges.
Failing masonry joints and a cracked crown let water into the chimney structure itself.
Without a cap, rain falls straight down the flue — an easy fix that prevents a lot of damage.
Damaged shingles adjacent to the chimney let water under the roof near the flashing.
Roofing cement smeared where proper metal flashing belongs is a common shortcut that fails within a few years.
How Union Fixes It
We find the real source — testing where the water actually enters, not just where the stain shows.
Proper metal flashing — step and counter-flashing installed the right way, not a smear of cement.
Re-seal & re-point — fresh sealant and, where needed, masonry repair around the base.
Replace damaged shingles — anything compromised around the chimney is repaired at the same time.
Backed in writing — our repair is warrantied, so the leak stays fixed.
Don’t Let a Small Leak Become a Big Repair
Protect Your Ceilings: Chimney leaks quietly ruin drywall, insulation and paint before you ever see a drop.
Prevent Rot: Persistent moisture rots roof framing and the wood around the chimney chase.
Stop Mold: Trapped water in the attic and walls is a fast track to mold. Sealing the leak stops it at the source.
Preserve the Masonry: Water freezing in the brick and mortar accelerates chimney deterioration every winter.
Serving Philadelphia & Surrounding Areas
12260 Townsend Road
Philadelphia, PA 19154
Phone: 215-464-6425
Union Roofing repairs chimney flashing and leaks across the city and the surrounding Montgomery, Bucks and Delaware county communities.
Chimney Leak & Flashing FAQs
That’s the classic sign of failed flashing or sealant. When it rains, water runs down the roof and finds the gap where the chimney meets the roof — a spot that stays dry the rest of the time. Repairing the flashing almost always solves it.
It depends on the extent of the damage and whether masonry work is needed. A straightforward flashing repair is a modest job; a full flashing replacement with re-pointing costs more. We give you an honest written quote after inspecting the chimney — and inspections are free.
Usually roofing — the flashing and sealant where the roof meets the chimney. Sometimes it’s the masonry crown or mortar joints. We diagnose which it is (often both) so the leak is fixed properly, not just patched.
In most cases a targeted flashing repair solves the leak with no need to touch the rest of the roof. If the surrounding shingles are also failing, we’ll tell you honestly and give you options.
Chimney Leaking When It Rains?
Book a free Philadelphia roof inspection — we’ll find why your chimney leaks and give you an honest quote to fix it for good.