How long a roof lasts
The most widely used planning figures come from HUD's estimated useful life table for capital needs assessments. They are what lenders and housing agencies plan with, not a promise for any one roof.
| Roof covering | HUD useful life |
|---|---|
| Asphalt shingles | 20 years |
| Cedar shingles or shakes | 25 years |
| Metal | 50 years |
| Slate | 75 years |
| Clay or concrete tile | 60 years |
| EPDM or TPO membrane (flat roof) | 15 years |
| Built-up roof with gravel | 20 years |
A "30-year" or "50-year" shingle is a warranty term, not a lifespan. HUD still plans asphalt shingles at 20 years. See roof warranties.
How old the houses are
In the town pages this site covers, most homes in Pennsylvania, New Jersey, Massachusetts, Connecticut and Rhode Island were built before 1980; in Florida the stock is younger, and most of it still predates 2000 (Census ACS 2020–2024; each state page gives the share: PA, NJ, MA, CT, RI, FL). By HUD's 20-year figure, a shingle roof on a house from the 1970s is not the first one the house has had.
That is a probability, not a diagnosis. The Census does not know when your roof was last replaced.
How to find your roof's age
- Paperwork. The contract or invoice from the last replacement, or the closing documents when you bought the house.
- Permit records. Boston and Philadelphia publish their permits as open data, searchable by address. Many other towns will look up a permit history on request.
- New Jersey is different. Replacing the covering on a detached one- or two-family house needs no permit there (N.J.A.C. 5:23-2.7), so there may be no record at all.
- Florida counts it by law from the last date 100 percent of the roof's surface was built or replaced (Fla. Stat. § 627.7011(5)(d)).
When the code decides for you
Some situations take the choice away:
- Two layers already on. No third layer may go on; the roof comes off to the deck (IRC R908.3.1.1; in Florida, FBC Existing Building 706.3).
- Slate or tile underneath. Neither can be roofed over.
- A water-soaked or deteriorated roof is not a base for a new layer.
- Florida's 25 percent rule. If more than a quarter of a roof or roof section is redone within 12 months, the whole roof or section has to meet the current code, unless it was built under the 2007 Florida Building Code or later (FBC Existing Building 706.1.1).
When it is not a replacement
A single leak on a roof with years of life left is usually a repair, which this line does not handle.
A roof with years left on it and one damaged area is a job for whoever does that kind of work. If you are not sure which you have, keep it or replace it? walks through the questions without a phone number on the page.
Winter
Replacements happen year-round, but cold weather slows some steps. See how long a roof replacement takes.
Questions
How old is too old for a shingle roof?
HUD’s useful-life table plans asphalt shingles at 20 years, even when the bundle says 30 or 50, which is a warranty term. By that figure, a house from the 1970s is not on its first shingle roof, though only the roof itself shows its condition.
How can I find out how old my roof is?
Check the contract or invoice from the last replacement or the closing documents, and look for permit records: Boston and Philadelphia publish permits as open data by address, and many towns will look up a permit history on request. In New Jersey a detached house may have no record, since its reroof needs no permit.
When does the building code require a new roof instead of another layer?
When two layers are already on, no third may go on and the roof comes off to the deck. Slate or tile underneath can’t be roofed over, and a water-soaked or deteriorated roof is not a base for a new layer.