The median home in Thornbury Township was built in 1994; there are 1,161 of them. Below: what the code asks of a replacement here, the permit, and the town’s own records.
New Roofing Costs connects homeowners with independent local roofing contractors. We do not perform roofing work.
This number connects homeowners who are planning a new roof or a full roof replacement with independent local roofing contractors. It is not for leak repairs or patch jobs. The call must come from the homeowner who decides on the roof. Calls may be recorded.
Permit
Under 34 Pa. Code § 403.1(b)(8), alterations to a house that make no structural change are outside the state code. So the township code office in Thornbury Township is the one to ask before work starts.
Source: 34 Pa. Code § 403.1(b)
Layers
IRC R908.3.1.1 forbids roofing over two existing layers, over slate or tile, or over a water-soaked roof. 27% of Thornbury Township’s homes were built before 1980; many have been reroofed before.
Ice barrier
IRC R905.1.2 calls for an ice barrier where Table R301.2 says so; in Pennsylvania the municipality completes that table. Ask the township code office or the contractor what Thornbury Township’s says.
Rules as read on October 24, 2026. Everything else the state requires: roof replacement in Pennsylvania.
Owners live in 883 of Thornbury Township’s occupied homes, or 77%. By year built, 13% before 1960, 27% before 1980; 35% went up in 2000 or later. (ACS 2020–2024.)
By building type: 55% detached houses, 26% attached single-family houses (rowhouses, twins and townhouses).
35% of homes here were built in 2000 or later. HUD’s useful-life table gives an asphalt-shingle roof 20 years, so roofs on houses from the early 2000s are reaching that age.
Of the 71 Chester County municipalities on this site, Thornbury Township has the 61st largest share of homes built before 1980: 27%, against a county range of 12% to 80%.
ZIP codes: 19319
| Place | Median built | Before 1980 | Owners | Row, twin | Hail days |
|---|---|---|---|---|---|
| Thornbury Township, Chester County | 1994 | 27% | 77% | 26% | 15 |
| Westtown | 1981 | 47% | 83% | 11% | 15 |
| Thornbury Township, Delaware County | 1997 | 30% | 93% | 17% | 13 |
| Birmingham | 1989 | 27% | 99% | 16% | 16 |
| West Chester | 1954 | 75% | 35% | 32% | 10 |
| West Goshen | 1978 | 53% | 72% | 10% | 10 |
Median built: median year the homes were built. Before 1980: share of homes built then. Owners: share of homes that are owner-occupied. Row, twin: share of homes that are rowhouses, twins or townhouses. Census ACS 2020–2024. Hail days: days with hail of 1 inch or larger within 10 miles, 2006–2025, NOAA Storm Prediction Center.
Since 2006 the National Weather Service has logged hail of 1 inch or larger on 15 separate days within 10 miles of Thornbury Township; the largest was 2.5 in on May 22, 2014. The most recent was April 4, 2025.
Federal major-disaster declarations for storms in Chester County since 2006: 5, most recently DR-4618, Remnants of Hurricane Ida, declared September 2021. (OpenFEMA.)
A report says hail fell near Thornbury Township, not that it damaged a roof. When wind or hail damage means a new roof.
Lifespans come from HUD’s capital-needs table, not from a brochure. More in the guides to shingles, metal, slate and flat roofs.
| Material | HUD useful life | Fits a house like | Watch for |
|---|---|---|---|
| Asphalt shingles | 20 years | Most pitched roofs; 55% of homes here are detached | Wind class set by the design wind speed (IRC Table R905.2.4.1) |
| Metal (standing seam, panels) | 50 years | Simple roofs with long, unbroken slopes | Standing seam that carries its own loads can skip the tear-off (R908.3.1) |
| Slate | 75 years | Older and historic houses | Sound slate can be reused (R908.5); broken slate cannot |
| Flat roof: EPDM or TPO | 15 years | Low-slope roofs and rear sections (26% of homes here are attached) | Coating is not a replacement |
A contractor who does $5,000 or more of home improvement work a year must be registered with the Pennsylvania Attorney General, and the number has to be on every contract and estimate (HICPA § 3, § 6). Ask for it before anyone starts on a roof in Thornbury Township, and search it.
The price side is in what a new roof costs in Pennsylvania; the paperwork side in checking a roofing contractor.
Ask Thornbury Township first. Under 34 Pa. Code § 403.1(b)(8), alterations to a house that make no structural change are outside the state code. So the township code office in Thornbury Township is the one to ask before work starts.
IRC R908.3.1.1 forbids roofing over two existing layers, over slate or tile, or over a water-soaked roof. 27% of Thornbury Township’s homes were built before 1980; many have been reroofed before.
By the Census Bureau’s American Community Survey (2020–2024), the median home in Thornbury Township was built in 1994, 27% of homes were built before 1980, 77% are owner-occupied.
Hail of 1 inch or larger was reported on 15 days within 10 miles of Thornbury Township from 2006 through 2025 (NOAA Storm Prediction Center). A report means hail fell nearby, not that a roof was damaged.
A contractor who does $5,000 or more of home improvement work a year must be registered with the Pennsylvania Attorney General, and the number has to be on every contract and estimate (HICPA § 3, § 6). Ask for it before anyone starts on a roof in Thornbury Township, and search it.
The full list: before you call.
Checked October 24, 2026. Laws and code editions change; the date says when these were last read at the source.