The median home in Londonderry Township was built in 1998; there are 975 of them. The rules below decide how much of the old roof has to come off and what goes under the new one.
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
Pennsylvania’s code leaves residential alterations without structural change to local ordinance (34 Pa. Code § 403.1(b)(8)). So the township code office in Londonderry 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. 40% of Londonderry Township’s homes were built before 1980, so count the layers before comparing quotes.
Ice barrier
Whether an eave membrane is a code item depends on the climate table the municipality filled in when it adopted the code (IRC R905.1.2, Table R301.2). Ask the township code office or the contractor what Londonderry Township’s says.
Checked against the code text on October 24, 2026. The state’s code edition and the rest of its rules: roof replacement in Pennsylvania.
Of 975 occupied homes in Londonderry Township, 916 (94%) are owner-occupied. Counting by decade, 9% before 1940, 15% before 1960, 40% before 1980 of the housing was in place, and 49% dates from 2000 on. (ACS 2020–2024.)
The housing is 84% detached houses, 9% attached single-family houses (rowhouses, twins and townhouses), 4% manufactured homes.
49% 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, Londonderry Township has the 37th largest share of homes built before 1980: 40%, against a county range of 12% to 80%.
ZIP codes: 19330
| Place | Median built | Before 1980 | Owners | Row, twin | Hail days |
|---|---|---|---|---|---|
| Londonderry Township, Chester County | 1998 | 40% | 94% | 9% | 11 |
| Highland | 1962 | 69% | 88% | 4% | 10 |
| Penn Township, Chester County | 2002 | 19% | 78% | 12% | 9 |
| West Fallowfield | 1978 | 53% | 78% | 0% | 10 |
| London Grove | 1997 | 26% | 96% | 7% | 10 |
| West Grove | 1971 | 59% | 77% | 21% | 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 11 separate days within 10 miles of Londonderry Township; the largest was 1.75 in on July 25, 2010. The most recent was September 7, 2023.
Chester County has had 5 federal major-disaster declarations for storms since 2006; the latest was DR-4618, Remnants of Hurricane Ida (September 2021). (OpenFEMA.)
Storm reports are what observers logged, not a measure of damage to any 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; 84% 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 | Low pitches and long runs | A complete standing-seam system may go over the old roof (R908.3.1) |
| Slate | 75 years | Older houses; 9% here predate 1940 | Can’t be roofed over; check the framing for the weight |
| Flat roof: EPDM or TPO | 15 years | Additions and porch roofs | Seams at walls and drainage |
Before signing for a roof in Londonderry Township, get the contractor’s PA registration number: the home improvement law requires registration with the Attorney General above $5,000 a year of such work, and the number on contracts and estimates (HICPA § 3, § 6).
Contracts, deposits and the right to cancel: checking a roofing contractor. What moves the price: new roof cost in Pennsylvania.
Londonderry Township’s ordinance decides. Pennsylvania’s code leaves residential alterations without structural change to local ordinance (34 Pa. Code § 403.1(b)(8)). So the township code office in Londonderry 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. 40% of Londonderry Township’s homes were built before 1980, so count the layers before comparing quotes.
By the Census Bureau’s American Community Survey (2020–2024), the median home in Londonderry Township was built in 1998, 40% of homes were built before 1980, 94% are owner-occupied.
Hail of 1 inch or larger was reported on 11 days within 10 miles of Londonderry Township from 2006 through 2025 (NOAA Storm Prediction Center). A report means hail fell nearby, not that a roof was damaged.
Before signing for a roof in Londonderry Township, get the contractor’s PA registration number: the home improvement law requires registration with the Attorney General above $5,000 a year of such work, and the number on contracts and estimates (HICPA § 3, § 6).
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.