Williamstown has 638 homes, and half of them were standing by 1938. 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
The state code does not cover a reroof that changes no structure (34 Pa. Code § 403.1(b)(8)). Whether Williamstown wants a permit is in its own ordinance; ask the borough code office before the old roof comes off.
Source: 34 Pa. Code § 403.1(b)
Layers
On a roof that already carries two layers, or slate or tile, the code allows no recover: it is a tear-off (IRC R908.3.1.1). 97% of Williamstown’s homes were built before 1980, so count the layers before comparing quotes.
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 borough code office or the contractor what Williamstown’s says.
Rules as read on October 24, 2026. Code edition, permit and contract rules for the whole state: roof replacement in Pennsylvania.
Owners live in 358 of Williamstown’s occupied homes, or 63%. By year built, 63% before 1940, 84% before 1960, 97% before 1980; 1% went up in 2000 or later. (ACS 2020–2024.)
By building type: 62% detached houses, 15% attached single-family houses (rowhouses, twins and townhouses), 14% buildings of two to four units.
On a house built before 1940, ask what the deck is (boards or plywood) and whether slate sits under the later layers: slate can’t be roofed over.
Of the 31 Dauphin County municipalities on this site, Williamstown has the 2nd largest share of homes built before 1980: 97%, against a county range of 31% to 100%.
| Place | Median built | Before 1980 | Owners | Row, twin | Hail days |
|---|---|---|---|---|---|
| Williamstown | 1938 | 97% | 63% | 15% | 3 |
| Williams Township, Dauphin County | 1950 | 83% | 86% | 4% | 4 |
| Tower City | 1938 | 93% | 74% | 21% | 3 |
| Wiconisco | 1938 | 86% | 87% | 3% | 4 |
| Lykens Borough | 1938 | 94% | 62% | 20% | 4 |
| Porter Township, Schuylkill County | 1948 | 80% | 84% | 13% | 1 |
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 3 days since 2006 with hail of at least 1 inch inside a 10-mile circle around Williamstown, topping out at 2 in on May 28, 2019. The most recent was June 26, 2023.
That is fewer than most places in the state on this site (median 12 days).
Federal major-disaster declarations for storms in Dauphin County since 2006: 5, most recently DR-4618, Remnants of Hurricane Ida, declared September 2021. (OpenFEMA.)
A report says hail fell near Williamstown, not that it damaged a roof. When wind or hail damage means a new roof.
Useful life is HUD’s planning figure, not a warranty. 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; 62% 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 | Standing seam that carries its own loads can skip the tear-off (R908.3.1) |
| Slate | 75 years | Older houses; 63% here predate 1940 | Never a base for a new layer (R908.3.1.1); heavy |
| Flat roof: EPDM or TPO | 15 years | Porches, additions, low-slope rears | Seams at walls and drainage |
Before signing for a roof in Williamstown, 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 price side is in what a new roof costs in Pennsylvania; the paperwork side in checking a roofing contractor.
Local ordinance, not the state. The state code does not cover a reroof that changes no structure (34 Pa. Code § 403.1(b)(8)). Whether Williamstown wants a permit is in its own ordinance; ask the borough code office before the old roof comes off.
On a roof that already carries two layers, or slate or tile, the code allows no recover: it is a tear-off (IRC R908.3.1.1). 97% of Williamstown’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 Williamstown was built in 1938, 97% of homes were built before 1980, 63% are owner-occupied.
Hail of 1 inch or larger was reported on 3 days within 10 miles of Williamstown 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 Williamstown, 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.