The median home in Derry Township was built in 1979; there are 10,432 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 51% 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. The state’s code edition and the rest of its rules: roof replacement in Pennsylvania.
Owners live in 6,347 of Derry Township’s occupied homes, or 63%. By year built, 8% before 1940, 21% before 1960, 51% before 1980; 18% went up in 2000 or later. (ACS 2020–2024.)
By building type: 50% detached houses, 22% attached single-family houses (rowhouses, twins and townhouses), 9% buildings of two to four units.
Of the 31 Dauphin County municipalities on this site, Derry Township has the 23rd largest share of homes built before 1980: 51%, against a county range of 31% to 100%.
ZIP codes: 17033 · 17036
| Place | Median built | Before 1980 | Owners | Row, twin | Hail days |
|---|---|---|---|---|---|
| Derry Township, Dauphin County | 1979 | 51% | 63% | 22% | 21 |
| Hummelstown | 1965 | 69% | 54% | 7% | 21 |
| South Hanover | 1996 | 31% | 71% | 19% | 20 |
| Conewago Township, Dauphin County | 1978 | 54% | 89% | 6% | 18 |
| Palmyra Borough | 1957 | 83% | 58% | 19% | 17 |
| North Londonderry | 1980 | 50% | 84% | 18% | 17 |
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 21 days since 2006 with hail of at least 1 inch inside a 10-mile circle around Derry Township, topping out at 1.5 in on June 3, 2023. The most recent was June 26, 2023.
That is more hail days than 95% of the places in the state on this site.
Remnants of Hurricane Ida (DR-4618, September 2021) is the latest of 5 federal storm declarations covering Dauphin County since 2006. (OpenFEMA.)
A report says hail fell near Derry 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; 50% 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; 8% here predate 1940 | Never a base for a new layer (R908.3.1.1); heavy |
| Flat roof: EPDM or TPO | 15 years | Low-slope roofs and rear sections (22% of homes here are attached) | Where the roof meets a wall or parapet |
Pennsylvania’s home improvement law (HICPA § 3, § 6) requires registration with the Attorney General from $5,000 a year of such work and puts the number on every estimate; ask for it in Derry Township and look it up.
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 51% 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 1979, 51% of homes were built before 1980, 63% are owner-occupied.
Hail of 1 inch or larger was reported on 21 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.
Pennsylvania’s home improvement law (HICPA § 3, § 6) requires registration with the Attorney General from $5,000 a year of such work and puts the number on every estimate; ask for it in Derry Township and look it up.
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.