The median home in Derry Township was built in 1962; there are 3,443 of them. What the code requires when that roof is replaced, and who signs off, is below.
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
The state code does not cover a reroof that changes no structure (34 Pa. Code § 403.1(b)(8)). So the township code office in Derry 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. With 75% of Derry Township’s homes were built before 1980, ask what is under the newest layer.
Ice barrier
IRC R905.1.2 calls for an ice barrier where Table R301.2 says so; in Pennsylvania the municipality completes that table. Derry Township’s answer is with the township code office.
Rules as read on October 24, 2026. Code edition, permit and contract rules for the whole state: roof replacement in Pennsylvania.
Owners live in 2,481 of Derry Township’s occupied homes, or 78%. By year built, 21% before 1940, 48% before 1960, 75% before 1980; 10% went up in 2000 or later. (ACS 2020–2024.)
By building type: 75% detached houses, 7% attached single-family houses (rowhouses, twins and townhouses), 6% buildings of two to four units, 11% manufactured homes.
Of the 12 Mifflin County municipalities on this site, Derry Township has the 4th largest share of homes built before 1980: 75%, against a county range of 52% to 93%.
ZIP codes: 17009 · 17044 · 17099
| Place | Median built | Before 1980 | Owners | Row, twin | Hail days |
|---|---|---|---|---|---|
| Derry Township, Mifflin County | 1962 | 75% | 78% | 7% | 6 |
| Burnham | 1952 | 87% | 74% | 8% | 7 |
| Lewistown | 1938 | 93% | 40% | 22% | 7 |
| Granville | 1971 | 73% | 78% | 3% | 6 |
| Brown | 1970 | 59% | 82% | 8% | 7 |
| Milford Township, Juniata County | 1976 | 59% | 80% | 3% | 4 |
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.
NOAA’s storm reports show 6 days since 2006 with hail of at least 1 inch inside a 10-mile circle around Derry Township, topping out at 2 in on June 16, 2022. The most recent was June 9, 2025.
That is fewer than most places in the state on this site (median 12 days).
A report says hail fell near Derry Township, not that it damaged a roof. When wind or hail damage means a new roof.
HUD’s useful-life figures are for planning; a warranty is a separate promise. For Derry Township’s houses: 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; 75% 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 | Roofs that will carry solar later | Standing seam that carries its own loads can skip the tear-off (R908.3.1) |
| Slate | 75 years | Older houses; 21% here predate 1940 | Sound slate can be reused (R908.5); broken slate cannot |
| Flat roof: EPDM or TPO | 15 years | Porches, additions, low-slope rears | 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 Derry Township, and search it.
The price side is in what a new roof costs in Pennsylvania; the paperwork side in checking a roofing contractor.
Derry Township’s ordinance decides. The state code does not cover a reroof that changes no structure (34 Pa. Code § 403.1(b)(8)). So the township code office in Derry 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. With 75% of Derry Township’s homes were built before 1980, ask what is under the newest layer.
By the Census Bureau’s American Community Survey (2020–2024), the median home in Derry Township was built in 1962, 75% of homes were built before 1980, 78% are owner-occupied.
Hail of 1 inch or larger was reported on 6 days within 10 miles of Derry 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 Derry 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.