How long does each roofing material last?
| Roofing material | Estimated life (years) |
|---|---|
| Asphalt shingles (3-tab) | 20 |
| Asphalt shingles (architectural) | 30 |
| Wood shakes or shingles | 25 |
| Metal | 40 to 80 |
| Clay or concrete tile | 100+ |
| Slate | 60 to 150 |
| Built-up roofing (flat) | 30 |
| Modified bitumen (flat) | 20 |
| TPO (flat) | 7 to 20 |
| EPDM rubber (flat) | 15 to 25 |
Source: InterNACHI Standard Estimated Life Expectancy Chart. InterNACHI notes that these are guidelines for normal wear with recommended maintenance, not guarantees.
How does the weather in Marin County affect roof life?
Marin is two roof climates in one county. West Marin, Mill Valley, Fairfax and the shaded canyons stay damp under fog and redwoods, which lets moss lift shingles and keeps decks wet. Inland and on south-facing slopes in San Rafael and Novato, summers are warmer and drier, and InterNACHI notes that hot climates drastically reduce asphalt shingle life.
How can I find out how old my roof is?
- Permit history. Most building departments can look up past permits for your address, including reroofs.
- Purchase paperwork. Your home inspection report and the seller's disclosures often note the roof's age or last replacement.
- Invoices and warranties. A roofing contract or manufacturer warranty registration shows the install date.
- A roofer's assessment. A licensed roofer can estimate remaining life from the materials and their condition, with photos.
How old are homes in Marin County?
San Rafael's median home dates to 1968 and Novato's to 1975, while older pockets in Mill Valley, Sausalito and the Ross Valley predate both. Tract neighborhoods in Terra Linda and Novato often carry 1990s or 2000s shingle roofs now reaching the end of a typical architectural shingle's life, and older hillside homes can have layers, complex valleys and past wood-shake roofs that raise fire-rating questions.
What does roof age mean for my insurance?
Insurers use roof age in underwriting. Beginning January 1, 2028, SB 1301 bars an insurer from refusing or nonrenewing a policy solely because of roof age when the policyholder pays for an independent inspection showing at least five years of useful life left. See our insurance guide.
Frequently asked questions
How long does a shingle roof last?
InterNACHI estimates about 20 years for 3-tab asphalt shingles and about 30 years for architectural shingles under normal conditions with maintenance.
How long does a metal roof last?
InterNACHI's chart estimates 40 to 80 years for metal roofing.
How long does a flat roof last?
It depends on the system. InterNACHI estimates about 30 years for built-up roofing, 20 for modified bitumen, 7 to 20 for TPO and 15 to 25 for EPDM rubber.
How do I find my roof's age?
Check your city's permit history for your address, your purchase inspection report and disclosures, and any roofing invoices or warranty paperwork, or ask a licensed roofer to assess it.
Sources
Sources reviewed November 11, 2026. Figures are published estimates and official fees, not quotes. Confirm prices, permits and requirements with your contractor and building department. This page is general information, not legal or insurance advice.