Ask Zello Roofing

Homeowner guide

How a roof sheds water — and where it leaks

A roof is a chain of layers that hand water to the next one. A leak is usually one handoff that failed.

The path water takes off your roof

  1. 1. Shingles

    The visible layer. Each course overlaps the one below so water runs down and off, never sideways under a seam.

  2. 2. Underlayment and ice and water shield

    The backup under the shingles. Ice and water shield is a self-sealing membrane used where water slows down or backs up, such as eaves and valleys.

  3. 3. Flashing

    Metal at chimneys, walls and other places where the roof meets something vertical. Water has to turn a corner here, which is why many leaks start at flashing.

  4. 4. Pipe boots

    Rubber-and-metal collars around plumbing vents. When the rubber cracks with age, water follows the pipe into the attic.

  5. 5. Ridge and vents

    Openings that let the attic breathe. They are capped and shingled so air gets out and rain stays out.

  6. 6. Gutters and downspouts

    Carry water from the eaves away from the fascia and foundation. Clogged gutters can push water back toward the roof edge.

On every replacement we install ice and water shield in eaves and valleys, lifetime pipe boots with rain collars, starter shingles, and ridge vent and caps. See what's included.

Common questions

Where do roof leaks usually start?

Most often where water has to change direction or pass a penetration: flashing at chimneys and walls, cracked pipe boots, valleys, and roof edges where water backs up. Missing or wind-lifted shingles are another common cause.

Why does my ceiling stain appear far from the leak?

Water often runs along the underlayment, rafters or a pipe before it drips, so the stain can show up several feet from where water actually gets in. A roof inspection traces it back to the source.

Can a leak be repaired instead of replacing the roof?

Often, yes. A single failed pipe boot, flashing joint or a few lifted shingles can usually be repaired. Repeated leaks, widespread shingle wear or a roof near the end of its life usually point to replacement.

Roof repair

What does ice and water shield do?

It is a self-adhering membrane installed under the shingles where water is most likely to back up, such as eaves and valleys. It seals around nails and adds a second line of defense.

What should I do if my roof is leaking right now?

Move valuables, catch the water, and call. We can inspect, document the damage, and tell you whether a repair or a replacement is the honest answer.

Storm and leak help

Roof leaking?

Call (540) 406-3589 for an inspection.

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