Half of the 1,250 homes in Pennington were built before 1953. 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
Under N.J.A.C. 5:23-2.7 a reroof of a detached one- or two-family house goes ahead without a permit or a notice to the construction office. Attached houses (10% of Pennington’s homes) and any work that touches the structure fall outside the rule.
Source: N.J.A.C. 5:23-2.7
Layers
New Jersey deletes the IRC’s reroofing definitions (N.J.A.C. 5:23-3.21(c)2.xxii); its layer rule for existing houses is in the Rehabilitation Subcode, which this site has not read yet. 71% of Pennington’s homes were built before 1980: ask how many layers yours has and whether the price is for a tear-off to the deck.
Source: N.J.A.C. 5:23-3.21
Ice barrier
New Jersey requires the eave membrane only where January averages 25 °F or colder, which the state says is Sussex County (DCA Bulletin 07-3). In Pennington it is the installer’s and the manufacturer’s call; ask whether the quote includes it.
Source: N.J.A.C. 5:23-3.21; NJ DCA Bulletin 07-3
Checked against the code text on October 24, 2026. Everything else the state requires: roof replacement in New Jersey.
Owners live in 941 of Pennington’s occupied homes, or 82%. Counting by decade, 37% before 1940, 57% before 1960, 71% before 1980 of the housing was in place, and 8% dates from 2000 on. (ACS 2020–2024.)
The housing is 70% detached houses, 10% attached single-family houses (rowhouses, twins and townhouses), 7% buildings of two to four units.
Older houses hide their history: ask the contractor to confirm the deck (board or sheet) and every layer above it before pricing, because slate or two layers mean a full tear-off.
Of the 12 Mercer County municipalities on this site, Pennington has the 6th largest share of homes built before 1980: 71%, against a county range of 19% to 79%.
| Place | Median built | Before 1980 | Owners | Row, twin | Hail days |
|---|---|---|---|---|---|
| Pennington | 1953 | 71% | 82% | 10% | 13 |
| Hopewell Township, Mercer County | 1977 | 53% | 91% | 9% | 8 |
| Lawrence Township, Mercer County | 1979 | 51% | 68% | 19% | 10 |
| Ewing | 1964 | 72% | 67% | 7% | 12 |
| Hopewell Borough | 1938 | 79% | 76% | 7% | 11 |
| West Amwell | 1975 | 54% | 89% | 2% | 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 13 separate days within 10 miles of Pennington; the largest was 1.75 in on July 23, 2008. The most recent was April 1, 2023.
At the county level, Pennington shares Mercer County’s record of 9 storm disaster declarations since 2006, the newest DR-4614 (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.
HUD’s useful-life figures are for planning; a warranty is a separate promise. For Pennington’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; 70% 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 | A complete standing-seam system may go over the old roof (R908.3.1) |
| Slate | 75 years | Older houses; 37% here predate 1940 | Sound slate can be reused (R908.5); broken slate cannot |
| Flat roof: EPDM or TPO | 15 years | Additions and porch roofs | Where the roof meets a wall or parapet |
Any business offering home improvements in Pennington must be registered with the New Jersey Division of Consumer Affairs, with the number on its contracts and ads (N.J.S.A. 56:8-138, 56:8-144); 47,473 registrations were active in October 2026.
Contracts, deposits and the right to cancel: checking a roofing contractor. What moves the price: new roof cost in New Jersey.
None for a detached one- or two-family house. Under N.J.A.C. 5:23-2.7 a reroof of a detached one- or two-family house goes ahead without a permit or a notice to the construction office. Attached houses (10% of Pennington’s homes) and any work that touches the structure fall outside the rule.
By the Census Bureau’s American Community Survey (2020–2024), the median home in Pennington was built in 1953, 71% of homes were built before 1980, 82% are owner-occupied.
Hail of 1 inch or larger was reported on 13 days within 10 miles of Pennington from 2006 through 2025 (NOAA Storm Prediction Center). A report means hail fell nearby, not that a roof was damaged.
Any business offering home improvements in Pennington must be registered with the New Jersey Division of Consumer Affairs, with the number on its contracts and ads (N.J.S.A. 56:8-138, 56:8-144); 47,473 registrations were active in October 2026.
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.