A contractor shows up and tells you that you need a new roof. Before you write a fifteen-thousand-dollar check, you need to know whether you actually do. Because a roof leak does not automatically mean a new roof — and most of the time, it doesn’t.
I’ve re-roofed houses and I’ve talked people out of re-roofing houses. The decision comes down to five things you can evaluate without ever getting up on the roof yourself.
The baseline question: how old is the roof?
Asphalt shingles have a real service life. Architectural (dimensional) shingles are rated for 25 to 30 years. Three-tab shingles run 15 to 20. If the roof is at or past that age, a repair is often still worth doing — but it’s borrowing time, and you should budget for replacement in the near term. If the roof is 10 years old and one section took storm damage, you repair. Age is context, not a verdict.
Sign 1: Missing or cracked shingles — almost always a repair
If you have isolated missing shingles after a storm, or a handful of cracked ones in one section, that is almost always a repair, not a replacement. A roofer with matching shingles can patch a section in a few hours. A hundred to five hundred dollars. The mistake is letting a contractor say “while we’re up there” and turning a patch into a replacement quote.
Where this gets complicated: if the shingles that blew off are from a discontinued product, you may not get a perfect color match. That’s an aesthetic issue, not a structural one, and it’s still a repair.
Sign 2: Granule loss in the gutters — monitor, don’t panic
After a heavy rain, check your gutters. Some granule loss — the coarse black material embedded in the shingle surface — is normal throughout the life of the roof. It accelerates in years 15 through 25 as shingles approach end of life.
A small amount of granules in the gutter isn’t an emergency. A thick layer, combined with shingles that are visibly thin or balding in spots or starting to curl at the corners — that’s a roof in its last few years. Monitor it, budget for replacement, but don’t call a roofer because of granules in the gutter alone. That’s a scare tactic.
Sign 3: A sagging or wavy roofline — this is a replacement
Stand back from the house and look at the roofline from the yard. A healthy roof has clean straight lines along the ridge and the field of the roof. Waves, a dip in the middle of a section, or a visible sag — that means the deck, the plywood or boards the shingles are nailed to, has failed. Wet rot from below. You cannot put good shingles over a compromised deck. That is a full replacement.
You can also see deck failure from inside the attic: if you go up on a warm day after a rain, look for soft spots or dark water staining in the sheathing, and probe soft areas with a screwdriver. Any give at all is a problem.
Sign 4: Flashing failures — get a repair price first
Most leaks that look like shingle failures are actually flashing failures. Flashing is the metal that seals the roof at chimneys, skylights, pipe penetrations, and valleys — the places where two roof planes meet or where something comes through the roof surface. Flashing can lift, corrode, or lose its sealant over time, and when it does, water gets in.
The leak shows up inside at the ceiling directly below the penetration. A homeowner looks up, sees water near the chimney, and assumes the roof is shot. Often it’s a two-hour flashing repair — re-bed the base flashing, run new counter-flashing, seal the step flashing — for a few hundred dollars.
Get a price for flashing repair before you agree to anything bigger. If a roofer tells you the leak is at the chimney or a pipe and the only fix is a new roof, get a second opinion.
Sign 5: Multiple shingle layers — now you may need to replace
Flip up a shingle at the edge of the roof and count the layers underneath. If there are already two layers of shingles on the house, most local codes and most roofers won’t add a third — you have to strip the whole roof to the deck first. Two layers also means the deck hasn’t been inspected or exposed in 20 to 40 years.
At that point, a full replacement usually makes practical sense: you’re paying for the tearoff labor anyway, and you get a chance to look at the deck and make any needed repairs to the sheathing before the new shingles go down.
The actual decision framework
Repair when:
- Damage is isolated to one section or a few shingles
- The underlying deck is solid (no sag, no rot)
- The roof is under 20 years old
- The problem is at a flashing point, not in the field of the roof
Replace when:
- The deck is sagging or showing signs of rot
- You already have two shingle layers
- The roof is at or past its rated service life AND showing widespread granule loss or curling
- The cost of repeated repairs is approaching replacement cost
A targeted repair can add five to ten years to a roof that is otherwise in reasonable shape. Don’t let anyone tell you the whole thing needs to come off until you’ve confirmed the deck is failing or the shingles are gone past the point of no return.
If you’re looking at a quote and you’re not sure which side of the line you’re on, send me a few photos — a wide shot from the yard, a close-up of the damaged area, and what the inside of the attic looks like near the leak. I’ll tell you what I’d actually do. Nine dollars and ninety-nine cents at hammondreengineered.com/report.
