Chimney & Roof Flashing Repair in Linden, NJ

What flashing does

A roof covered in shingles is pretty good at shedding water on its own. The weak spots are the places where the roof is interrupted: a chimney coming through it, a wall rising beside it, a skylight, a vent pipe, or a valley where two slopes meet. Flashing is the metal - usually aluminum, galvanized steel or copper - that seals those joints. If it's bent, rusted, loose or just installed wrong, water gets in.

Why chimneys leak so often in Linden

A lot of Linden homes were built with brick chimneys that are now 60, 80 or 100 years old. Over time the mortar between the bricks wears away, the flashing gets patched with tar and caulk instead of being replaced, and freeze-thaw winters slowly open up small gaps. Chimney leaks are one of the most common roof calls in older parts of the city.

Signs of a chimney or flashing leak:

• Water stains on the ceiling or wall right beside the chimney
• Damp brick or white staining (efflorescence) on the chimney inside the attic
• Rust, gaps or loose metal around the base of the chimney
• Thick layers of tar or caulk around the chimney - a sign of past patching
• Crumbling mortar joints or a cracked chimney crown on top
• Leaks around a skylight frame, a bathroom vent or the plumbing vent pipes

How chimney flashing is supposed to work

A properly flashed chimney has two layers of protection:

• Step flashing - individual L-shaped pieces woven in with each course of shingles up the sides of the chimney, so each piece overlaps the one below it.
• Counter-flashing - a second layer of metal set into a groove cut into the mortar joints of the chimney, folding down over the step flashing.

On the uphill side of wider chimneys there should also be a small peaked diverter called a cricket or saddle, so water and snow don't pile up behind the chimney.

Caulk and roofing tar can stop a leak for a season, but they dry out and crack. If your chimney is "fixed" with a thick layer of tar, it will leak again.

What the repair involves

• Removing the old flashing and any patching material
• Repointing loose mortar where the counter-flashing sits, so it has something solid to seal into
• Installing new step flashing and counter-flashing, plus a cricket where needed
• Replacing shingles around the chimney
• Checking the chimney crown and cap, since water coming in from the top can look like a flashing leak

Other flashing problems

Vent pipes: the rubber boot around a plumbing vent cracks with age and sun. A new pipe boot is one of the cheapest and most common leak repairs.
Skylights: leaks often come from failed flashing around the frame rather than the glass itself.
Walls: where a lower roof meets a second-story wall, step flashing behind the siding is what keeps water out.
Valleys: worn or poorly built valleys carry a lot of water and are a frequent leak point.