Repair or Replace? How to Tell If You Actually Need a New Roof

You probably need a new roof if damage is spread across several sections rather than one spot, if the shingles are shedding granules into your gutters, or if daylight and water stains show up in the attic. If the problem is one small area on a roof under about 10 years old, you probably need a repair. A common rule says to replace when repairs would cost more than 30% of a new roof.

That rule is easy to apply once you know what a new roof costs. It is also a good defense against a contractor who tells you the whole roof has to go after a five-minute look.

Start with age and what kind of roof you have

The first question is how old the roof is, because age tells you how much life is left. Kin’s 2026 guide gives these average lifespans:

Material	Average lifespan
3-tab asphalt shingles	15 to 20 years
Architectural shingles	25 to 30 years
Metal	40 to 70 years
Clay or concrete tile	50 to 100 years
Slate	100+ years

Other sources are more generous. Roof Observations lists 12 to 25 years for 3-tab, 20 to 35 for architectural and 25 to 40 for premium shingles. This Old House gives 30 to 35 years for asphalt in general. The spread is real, and climate, attic ventilation and the quality of the first install all push it around. This Old House offers a simple guide on age: repair roofs under 10 years old with localized problems, and replace roofs over 15 years old with widespread damage.

The checklist you can do yourself

You can learn a lot without going near the roof. Start on the ground with binoculars, then go inside.

From the ground, look for these. IKO’s guide lists the first four.

• Missing shingles, or shingles lying in the yard
• Cracked or lifted shingles
• Bare black asphalt where the surface granules are gone
• Clogged gutters
• A sagging or drooping roofline, which Kin says can signal rot or moisture damage to the supports
• Moss, mold or algae that traps moisture
• Heavy granule buildup in the gutters, which Kin flags when it shows up years after installation
• Cracked, missing or rusted flashing around chimneys, skylights and vents

From inside the house, look for these.

• Daylight coming through the roof boards
• Water stains or warped wood
• Damp insulation or a musty smell
• Ceiling stains in more than one room

IKO is clear that unless you have experience working at heights and the right safety equipment, you should limit your own checks to the ground and leave a full inspection to a roofer.

What counts as widespread

The line between repair and replace is how much of the roof is affected. Count the number of sections with curling, cracking or missing shingles. One slope with a few missing shingles after a storm is a repair. Every slope with curled edges is a roof at the end of its life.

Signs that point to replacement, from the checklist above:

• Damage across several sections
• Granule loss across the roof
• Sagging
• Daylight or leaks in more than one place
• Mold or rotted decking

Signs that point to repair:

• A single leak traced to flashing or a vent boot
• A handful of storm-damaged shingles
• A roof under 10 years old

The 30% rule, with numbers

Kin says replacing is usually smarter if repairs cost more than 30% of a new roof. To use that, you need a price for the new roof.

This Old House’s October 2026 guide uses 2026 Homewyse data and an average U.S. roof of about 1,700 sq ft:

Size	Asphalt shingles
1,000 sq ft	$5,160
1,500 sq ft	$7,740
2,000 sq ft	$10,320
2,500 sq ft	$12,900

Roof Observations, which includes tear-off, lists $5.60 per sq ft for 3-tab, $6.15 for architectural and $7.65 for premium. At 1,700 sq ft that is $9,520, $10,455 and $13,005.

Now apply the rule to a 1,700 sq ft roof:

• Using This Old House’s $8,772: 30% is 0.30 x $8,772 = $2,632
• Using Roof Observations’ architectural figure of $10,455: 30% is 0.30 x $10,455 = $3,137

So a repair quote around $2,600 to $3,100 is where the rule says to start thinking about replacement. A $450 flashing repair is far below that and is an easy yes. A $4,000 repair quote on a 20-year-old roof is above it, and you should ask for a replacement quote next to it.

When a repair is false economy

Kin says that if a roof is near the end of its expected life, repairs are often temporary. The sum of three small repairs over five years can pass the 30% line without anyone noticing.

Think about how long you will stay, too. Kin suggests a new roof makes sense if you plan to stay 20 or more years. If you are selling soon, a minimal repair may be enough, although a new roof can help the listing.

Two other things can tip the decision.

• If the roof already has two layers, Roof Observations says both must come off before a new one goes on.
• If the decking is rotted, it has to be replaced. Roof Observations notes that deteriorated sheathing found during replacement must be replaced, which adds cost. Kin lists hidden costs such as removing old layers, repairing decking and disposing of debris.

What replacement costs beyond shingles

A few cost drivers change the quote more than shingle brand does.

• Pitch. Roof Observations says steep roofs, over 6/12, can add up to 50% to labor costs, and complex roofs can raise the price by up to 50%. The Roof Pitch Calculator tells you where yours falls.
• Tear-off. Removing and disposing of old roofing typically adds about $1 to $3 per sq ft (Roof Observations).
• Size. Roofers price in squares of 100 sq ft, so a 2,000 sq ft roof is 20 squares. The Roof Area Calculator converts your house footprint and pitch into roof area.
• Material. The Roofing Shingle Calculator counts bundles for a given area.

How to avoid being upsold

Fear of being upsold is reasonable. Here is how to protect yourself.

1. Do your own ground and attic checks first, using the list above.
2. Ask the contractor to show you the damage with photos or by pointing it out on your roof, not only by telling you.
3. Ask for a written repair quote and a replacement quote for the same problem.
4. Divide the repair quote by the replacement quote. If it is under 30%, repair is likely sensible. Over 30% on an older roof, replacement deserves a look.
5. Get a second opinion from a contractor who is not selling you the first one.
6. If storm damage may be involved, call your insurance agent. IKO suggests the adjuster and contractor meet at your home to work together, and says to keep water out until the work starts.

Use the Roofing Cost Calculator to build your own estimate before the quotes arrive.

Questions to put on the quote

Whatever the contractor recommends, ask for these in writing so two bids can be compared line by line.

• How many layers of shingles are on the roof now, and does the price include tearing off all of them?
• What shingle line is being installed, and what is its stated lifespan?
• What happens if the decking underneath is rotted? Ask for the price to replace it before work starts, since it is a common surprise.
• Is flashing around the chimney, skylights and vents being replaced, or reused?
• Is disposal included?

A bid that answers all five is easier to trust, and easier to compare, than a single total.

What to do next

1. Find out the roof’s age and material. Look at the receipt, the permit or the home inspection report.
2. Walk the ground check and the attic check with a flashlight.
3. Count affected sections and compare to the lists above.
4. Price a replacement on your roof size.
5. Get at least one written repair quote and one written replacement quote.
6. Apply the 30% rule.

If the roof is in its last third of life and the repair is more than 30% of replacement, replace. If the roof is under 10 years old, the damage is local and the repair is cheap, repair it and write down the date.

Sources

• Kin, When to Replace Your Roof (updated July 2026)
• This Old House, New Roof Cost (updated October 2026)
• Roof Observations, Asphalt Shingle Roof Cost Guide (updated January 2026)
• IKO, Check Your Roof for Damage