Roof repair or replacement? How to tell

Where most leaks really start

A roof rarely fails everywhere at once. Most leaks come from a handful of weak points:

• Pipe boots. The rubber collar around plumbing vents dries out and cracks in the sun, often years before the shingles wear out.
• Flashing. The metal where the roof meets a wall, chimney, or skylight can pull loose or rust through.
• Valleys. Where two slopes meet, water runs heavy and finds any gap.
• Wind damage. A few missing or creased shingles can let water in under the rest.
• Exposed nails. Nail heads left uncovered rust and let water run down the shank.

Every one of these is a repair. If someone quotes a full roof for a single cracked pipe boot, get a second opinion.

Signs a repair will do

• The leak is in one spot, and you can see a likely cause near it.
• The damage is limited to a few shingles or one slope.
• The rest of the shingles still lie flat and hold their granules.
• The roof is well short of its expected life.

Signs it's time to replace

• Age. Basic three-tab shingles often last 15 to 20 years and architectural shingles 25 to 30, less under hard sun, heat, and hail. A roof near those numbers will keep needing repairs.
• Granule loss. Bare, shiny patches on the shingles, or gutters full of granules, mean the asphalt is exposed and wearing out.
• Curling, cupping, or cracking across several slopes, not just in one spot.
• Repeat leaks. Leaks in more than one place, or leaks that come back after repairs.
• Soft or sagging decking. If the roof feels spongy underfoot or sags between rafters, the wood underneath has been wet for a while.
• Layers. Most building codes don't allow a new roof over two existing layers, and a tear-off lets you see the decking anyway.

Do the math on years left

A repair is money well spent when the roof has years left to give. If the repairs you expect over the next few years start adding up toward the cost of a new roof, a replacement usually wins. On an older roof, ask for both prices so you can compare.

Questions to ask any roofer

• Can you show me photos of the problem?
• What caused it, and will this repair stop it?
• Is the repair warrantied, and for how long?
• If I repair it now, how many years do you expect before I need a new roof?
• Can I get the estimate in writing?