Seal the Spots Where Water Finds a Way In

Chimney flashing, roof vent, and penetration repair services in Manhattan, Brooklyn, Queens, The Bronx, Staten Island and Long Island

Every time something cuts through your roof, it creates an opening where water can enter if the seal fails. Chimneys, plumbing vents, exhaust fans, and skylights all require flashing or boots that prevent water from running down the sides and into your attic. When these seals crack, rust, or pull away from the surface, you see water stains on the ceiling near the penetration or notice dripping during rain.


Gemz Construction repairs and replaces chimney flashing, roof vents, and related components to restore the weatherproof seal around roof penetrations. We remove old flashing that has rusted or separated, install new metal flashing that fits the shape of the penetration, and seal the edges with roofing cement or caulk rated for exterior use. Vent boots are replaced when rubber collars crack or tear, which usually happens after years of sun exposure.


If you see leaks near a chimney or vent in your home throughout Manhattan, Brooklyn, Queens, The Bronx, Staten Island or Long Island, reach out to schedule a flashing inspection before water spreads to the decking.

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Why these repairs matter more than size suggests

Flashing repairs start with removing shingles around the penetration to expose the existing flashing and check for rust, separation, or improper installation. We fabricate new flashing from galvanized steel or aluminum, bend it to fit the angle where the penetration meets the roof, and slide it under the shingles so water runs over the flashing instead of behind it.


Once the flashing is replaced, you will no longer see water stains spreading across your ceiling after storms. The attic stays dry around the base of the chimney or vent pipe, and insulation in that area does not become damp or compressed. Proper flashing redirects water back onto the roof surface where it flows into the gutter system.


Vent boot replacement involves removing the damaged rubber collar, cleaning debris from the vent pipe, and installing a new boot with a collar that fits snugly around the pipe. We secure the base of the boot under the surrounding shingles and seal the edges to prevent wind-driven rain from entering. These repairs are often completed in a few hours, but they prevent leaks that can damage ceilings and walls over time if left unaddressed.

What homeowners usually ask about flashing work

People throughout Manhattan, Brooklyn, Queens, The Bronx, Staten Island and Long Island often want to know how long flashing lasts, whether it can be repaired without replacing shingles, and what causes it to fail in the first place. Most of these questions come from seeing a small leak and wondering if it will turn into something bigger.

What causes chimney flashing to fail?
Flashing fails when the sealant dries out and cracks, when rust eats through the metal, or when the flashing pulls away from the chimney due to thermal expansion. Wind can also lift shingles and expose the edges of the flashing to water.
How do I know if my vent boot needs replacement?
If the rubber collar around the vent pipe is cracked, torn, or pulling away from the pipe, the boot needs replacement. You may also see water stains on the ceiling directly below the vent.
Can you repair flashing without replacing shingles?
In some cases, yes, but we usually need to remove a few shingles around the penetration to install new flashing correctly. We reuse the shingles if they are still in good condition, or we replace them if they are damaged.
How long does new flashing last?
Metal flashing typically lasts twenty to thirty years if installed correctly and sealed properly. Vent boots last ten to fifteen years before the rubber collar degrades from sun exposure.
What happens if flashing is left unrepaired?
Water continues to enter through the gap, soaking the roof decking and insulation. Over time, the wood around the penetration rots, and the leak spreads to other areas of the attic and ceiling.

If you notice water stains near a chimney, vent, or skylight in your home, Gemz Construction can inspect the flashing and vent boots and complete repairs before the leak spreads. Get in touch to schedule a visit in Manhattan, Brooklyn, Queens, The Bronx, Staten Island or Long Island.