You should replace your roof when shingles are curling or balding, when leaks or water stains show up indoors, or when an asphalt roof passes 20 to 25 years of age. Any one of those is a strong signal; two or more together means it's time to plan the job, not patch it.
A roof rarely fails all at once. It tells you for years before it leaks, and reading those signs early lets you replace on your schedule instead of during an emergency after a storm.
The signs your roof is done
Walk the perimeter, look up from the yard with binoculars, and check the attic. Watch for:
- Curling or cupping shingles — edges lifting or centers dishing means the asphalt has dried out and lost its seal.
- Granule loss and bald spots — the gritty granules protect the shingle from UV. Bare black patches, or granules collecting in your gutters, signal advanced wear.
- Missing shingles — gaps after wind events expose the deck and underlayment.
- Leaks or attic water stains — brown rings on ceilings or dark streaks on rafters mean water is already getting in.
- Daylight through the roof deck — if you can see light between boards from the attic, water can follow.
- Age — asphalt roofs typically last 20 to 25 years. Past that, even a roof that looks okay is living on borrowed time.
One curled shingle isn't a crisis. Widespread curling across a slope, granules filling the gutters, and a roof pushing 25 years together tell a clear story.
Repair or replace?
A few missing shingles after a storm, or a single flashing leak, is a repair. Replacement makes more sense when:
- The damage is widespread, not isolated to one spot.
- The roof is near or past its expected lifespan.
- You're patching repeatedly — chasing leaks year after year costs more than one clean replacement.
- The deck is compromised — soft spots or rot underneath mean shingles alone won't fix it.
Spending repair money on a 24-year-old roof is rarely worth it. That cash is better put toward a replacement that resets the clock for another two to three decades.
How long different shingles last
Lifespan depends partly on what's up there now:
- 3-tab shingles last roughly 15 to 20 years. If your home has these and they're past 15, start watching closely.
- Architectural shingles last about 25 to 30 years and carry better wind ratings.
Climate matters too. Harsh sun, big temperature swings, and frequent storms shorten any roof's life. If you're choosing your next roof, our comparison of architectural vs. 3-tab shingles lays out the tradeoffs.
If you're climbing into the attic and see daylight or water staining on the deck, get a professional eval before the next big rain. Some signs you can't see from the ground.
Planning the replacement
Once you've decided to replace, the next question is how much material you need. The estimate comes down to your roof's surface area in squares (one square equals 100 sq ft of surface), your shingle type, and a waste allowance — 10% for a simple gable, 15% for hips and valleys.
- Measure your roof's footprint and pitch.
- Convert to squares using the slope factor, then add waste.
- Multiply squares by bundles per square (3 for standard shingles, 4 for heavy designer).
Our guide on how many bundles of shingles per square walks the full calculation, and the roofing calculator does the arithmetic so your budget is in the right ballpark before you call anyone. While you're sizing, remember that synthetic underlayment covers about 400 sq ft per roll — it goes down beneath every new shingle.
The wrap-up: replace your roof when the signs stack up — curling, granule loss, missing shingles, leaks, daylight through the deck, or simply age past 20 to 25 years. Plan ahead, get a reliable material estimate from the roofing calculator, and replace on your terms. A two-story or steep tear-off is a job for licensed professionals — this is a planning guide to help you scope and budget the work, not a DIY install manual.