Planning & safety
Repair or replace: the signs, the maths and the timing
A leak does not always mean a new roof, and a dry ceiling does not mean the roof is fine. Age, signs and a simple sum decide it.
Three questions
Most repair-or-replace decisions come down to three questions:
- How old is the roof, against its expected life? A 10-year-old architectural roof with a leak is a repair; a 26-year-old one may not be.
- Is the problem local or general? A failed pipe boot is local. Granule loss, curling and brittle shingles everywhere are general: the roof is wearing out.
- What does each option cost per year of roof it buys? That sum is below.
Signs you can see from the ground
You do not need to climb. Binoculars from the yard and a flashlight in the attic show most of it.
| Sign | What it usually means | Typical answer |
|---|---|---|
| A few missing or creased shingles after a storm | Wind damage on an otherwise sound roof | Repair |
| Leak at a chimney, wall or skylight | Flashing failure | Repair (reflash) |
| Leak around a vent pipe | Cracked pipe boot | Repair |
| Granules in the gutters, bald or dark patches | The shingles’ protective surface is wearing away | Replacement within a few years |
| Curling, cupping or cracked shingles across a slope | Age, heat, poor ventilation | Replacement within a few years |
| Shingles lost in ordinary storms, repeatedly | Sealant strips and mat are failing | Replacement |
| Daylight through the deck, stains on many rafters | Widespread leaks or condensation | Inspection; often replacement and ventilation work |
| A sagging roof line | Possible deck or structural problem | Structural inspection first |
The replacement planner combines age, material, climate, ventilation and these signs into an expected replacement window.
Common repairs
Most roof leaks are at the flashings, not in the field of the roof: pipe boots whose rubber has cracked, step flashing behind siding, chimney counter flashing, and valleys. Each is a contained repair. Published 2025 cost surveys put typical repairs at about $150 to $400 for a shingle patch, $150 to $300 for a pipe boot, $200 to $500 for flashing and $400 to $1,200 for chimney reflashing, with a minimum service charge for any visit. The repair cost calculator prices them with access and quantity, and the flashing guide explains each piece. The step flashing calculator counts what a sidewall or chimney needs.
The sum that settles it
Divide each option’s cost by the years of roof it buys.
A 24-year-old architectural roof with a valley leak
- Repair: $900 for the valley, buying perhaps 3 more years before the roof needs replacing anyway: $300 a year
- Replacement now: about $13,750 for 22 squares at the survey mid-point, over 27.5 years, plus $150 a year maintenance: $650 a year
The repair is cheaper per year, so repairing and planning the replacement for three years out is reasonable, provided the rest of the roof is sound. If a second and third leak follow, the repairs add up and the sum flips.
The replacement figure is from the lifespan and cost per year calculator; the range for your roof from the replacement cost calculator.
Timing a replacement
If the window is within a few years, plan rather than wait for a failure:
- Season. Late spring to early autumn is easiest for asphalt (the sealant strips need warmth), but demand peaks then too; a late-autumn booking can be cheaper if the weather holds.
- After storms, prices rise and crews are scarce.
- Combine work. Replace gutters, add ridge ventilation, fix soffits and reinsulate the attic at the same time: the scaffolding, dumpster and disruption are already paid for.
- Before solar. If panels are coming, reroof first; removing and reinstalling an array costs thousands.
- Before selling, a roof near its end will be found by the buyer’s inspector and negotiated down; a new roof is a selling point.
Overlay or tear-off?
Laying new shingles over one old layer saves the tear-off, but the code allows only one overlay, it hides the deck, and it adds weight and heat. Most roofers recommend tear-off on a full replacement; tear-off, layers and disposal covers the rules.
Insurance
Storm damage may be covered by a homeowner’s policy, wear and age usually are not. Read the policy and talk to the insurer before agreeing a scope with a contractor; this site gives no insurance advice beyond that.
Getting an honest opinion
A roofer selling replacements has an interest in finding one; a home inspector or a roofer paid for an inspection report does not. For an older roof with a single leak, paying for an independent inspection is often worth it. How long roofs last gives the age benchmarks, and how to read a roofing estimate helps compare what comes back.