The short answer: Repair when the damage is localized, the roof still has years of useful life left for its material, and it is the roof's first covering. Replace when the roof is at or near the end of its expected lifespan, damage is widespread, leaks are recurring, or the deck is sagging. The two biggest deciding factors are your roof's age relative to its material's lifespan and how extensive the damage is. When repeated repair bills start approaching the cost of a new roof, replacement is usually the smarter money.
Start with your roof's age and material
Every roofing material has a predictable service life, and where your roof falls on that curve is the first thing to establish. A roof in the last few years of its rated life is a replacement candidate even if today's damage looks minor, because more problems are coming.
| Material | Typical lifespan |
|---|
| 3-tab asphalt shingles | ~20 years[1] |
| Architectural (dimensional) asphalt shingles | ~30 years[1] |
| Wood shakes/shingles | ~25 years (some sources longer)[1] |
| Metal | ~40–80 years[1] |
| Clay or concrete tile | 100+ years[1] |
| Slate | ~60–150 years[1] |
These are estimates — actual life depends on "local weather conditions, building and design, material quality, and adequate maintenance."[1] A south-facing asphalt roof in a harsh climate ages faster than the chart suggests.
Signs that point to replacement
A few isolated missing shingles or a single flashing leak usually call for a repair. These signs, by contrast, lean toward replacement:
- Granules filling the gutters. Asphalt shingles shed their protective granules as they wear out; heavy granule loss signals the roof is near the end.[2]
- Curling, cupping, or brittle shingles. Edges curling upward or shingles that crack when gently pressed indicate age-related failure.[2]
- Multiple leaks in different locations. Scattered leaks suggest the roof system as a whole is failing, not a single flashing detail.[2]
- Visible sagging between the rafters. A dipping roofline can mean a compromised deck or structural moisture damage — a serious, replacement-level problem.[2]
It pays to inspect the leak-prone areas — valleys, around the chimney, and roof penetrations — about twice a year so you catch trouble early.[2]
The "25% rule" and what building codes actually require
You will often hear a "25% rule": if roughly a quarter or more of the roof is damaged, replace the whole thing. It is worth understanding what this is and is not. The 25% figure is a common insurance and adjuster guideline, not a universal building code — "If roughly a quarter of the roof surface or more is damaged in a single event, many carriers consider full replacement," but "the 25% rule is not a universal law."[3] Your policy and local codes govern the actual outcome.
What is code in much of the U.S. concerns roofing layers. Under the International Residential Code, "no more than two layers are allowed upon completion of installation," and a complete tear-off is required when the existing roof is water-soaked or too deteriorated to serve as a base, when it is slate or tile, or when it already has two or more layers.[4] In practice this means if your home already has two shingle layers, you cannot simply add a third — a full tear-off and replacement is mandatory. (Local codes vary, so confirm with your building department.)
What it costs
Roof pricing is usually quoted per "square" (100 square feet) or per square foot, and it swings widely with material, roof size, pitch, and local labor. National figures give a planning range:
- Full replacement (asphalt, average home): national averages cluster from about $9,600 to $15,400, with This Old House citing roughly $15,439 for a 2,000-square-foot asphalt roof and HomeAdvisor a national average near $9,607.[5][7]
- Per square foot (installed): commonly $4–$11 for asphalt, averaging around $7, and much higher for premium materials.[7] This Old House puts asphalt near $5/sq ft, metal near $18.60/sq ft, and clay tile above $21/sq ft.[5]
- Repairs: anywhere from about $150 for a minor fix up to several thousand dollars for major work.[6]
Labor is the dominant cost in a replacement — This Old House pegs it at roughly 65% of the total[5] — which is one reason repeated small repairs add up faster than homeowners expect. On the upside, a new roof can recoup 20% to 50% of its cost at resale.[7]
How to decide: a practical framework
Weigh these factors together rather than in isolation:
- Age vs. lifespan. If the roof is within a few years of its material's rated life, lean replacement.[1]
- Extent of damage. Localized damage favors repair; widespread damage, multiple leaks, or deck sag favors replacement.[2]
- Existing layers. If two layers are already present, code likely forces a tear-off.[4]
- Repair math. When cumulative repairs approach replacement cost, replace.[5]
- Shingle matching. Discontinued colors or lines make patch repairs stand out, nudging toward replacement for appearance.
- Plans to sell. A fresh roof aids a sale and recoups part of its cost.[7]
- Insurance posture. How your policy treats the damage (see below) can shift the economics.
Insurance considerations
Whether your roof is covered depends on the cause. Standard homeowners policies generally cover sudden, accidental perils such as windstorm, hail, and the weight of ice or snow — but they exclude flood and, importantly, gradual wear: "Your insurance policy will not cover damage due to lack of maintenance."[8] So storm or hail damage to a well-kept roof is typically covered, while an old roof that simply wore out is not.
Roof age also affects coverage and payout. The Insurance Information Institute notes that if a roof is over 20 years old when you apply for coverage, "most insurance companies will require it to pass an inspection," some insurers decline older roofs, and older roofs are often covered only at actual cash value (ACV) — with depreciation subtracted — rather than full replacement cost value (RCV).[9] That ACV-versus-RCV distinction can mean thousands of dollars out of pocket, so check your policy before you file.
Hiring a roofer: what to verify
Roofing attracts storm-chasing operators, so vet contractors carefully. The National Roofing Contractors Association recommends confirming a permanent place of business, license, and tax ID; requesting current certificates of both liability insurance and workers' compensation "in effect through the duration of your job"; getting references and a written proposal with complete specifications, start and completion dates, and payment terms; and checking for complaints.[10] And keep "a healthy skepticism about the lowest bid" — if it sounds too good to be true, it usually is.[10]
Questions worth asking:
- Are you licensed and insured for both liability and workers' comp — may I see current certificates?
- Will this be a tear-off or an overlay, and does code require a tear-off in my case?
- What is the manufacturer's material warranty, and what is your workmanship warranty?
- How will you protect and re-flash the valleys, chimney, and penetrations?
- Is attic ventilation adequate, and will you correct it if not?
Don't overlook attic ventilation
Whether you repair or replace, ventilation affects how long the roof lasts. ENERGY STAR notes that good attic airflow "moves super-heated air out of the attic, protecting roof shingles and removing moisture," and helps keep the attic cold enough to reduce ice dams.[11] Make sure soffit vents are not blocked by insulation. Poor ventilation can shorten shingle life and quietly undermine an expensive new roof.
Frequently asked questions
Can I just put new shingles over the old ones?
Sometimes — but only if you currently have a single layer and local code allows it. Codes generally cap a roof at two layers, and a tear-off is required if the existing roof is deteriorated, is slate or tile, or already has two layers.[4]
Will my insurance pay for a new roof?
If the damage came from a covered peril like wind or hail and the roof was maintained, likely yes — though older roofs may be paid at actual cash value rather than full replacement cost. Wear-and-tear and neglect are not covered.[8][9]
How do I know if it's just one bad spot or the whole roof?
A single localized leak with the rest of the roof in good shape is a repair. Widespread granule loss, curling shingles, leaks in multiple places, or a sagging deck point to a whole-roof problem and replacement.[2]