Knowlton has 1,207 homes, and half of them were standing by 1978. Below: what the code asks of a replacement here, the permit, and the town’s own records.
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
New Jersey treats a new covering on a detached one- or two-family house as ordinary maintenance: no permit, no notice (N.J.A.C. 5:23-2.7). In Knowlton, 91% of homes are detached. An attached house, or work on rafters and beams, is not covered.
Source: N.J.A.C. 5:23-2.7
Layers
The state strikes the IRC reroof definitions from its code (N.J.A.C. 5:23-3.21) and leaves existing houses to the Rehabilitation Subcode, not yet checked here. 53% of Knowlton’s homes were built before 1980, so get the layer count and a tear-off price in writing.
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 Knowlton 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. Code edition, permit and contract rules for the whole state: roof replacement in New Jersey.
Owners live in 1,023 of Knowlton’s occupied homes, or 88%. Counting by decade, 27% before 1940, 36% before 1960, 53% before 1980 of the housing was in place, and 9% dates from 2000 on. (ACS 2020–2024.)
The housing is 91% detached houses, 4% manufactured homes.
Of the 22 Warren County municipalities on this site, Knowlton has the 13th largest share of homes built before 1980: 53%, against a county range of 24% to 89%.
ZIP codes: 07832 · 07833
| Place | Median built | Before 1980 | Owners | Row, twin | Hail days |
|---|---|---|---|---|---|
| Knowlton | 1978 | 53% | 88% | 3% | 8 |
| Hope | 1972 | 62% | 88% | 2% | 4 |
| Blairstown | 1975 | 62% | 95% | 2% | 9 |
| Belvidere | 1938 | 89% | 57% | 3% | 3 |
| White | 1991 | 35% | 76% | 2% | 2 |
| Liberty | 1968 | 59% | 90% | 1% | 5 |
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 8 separate days within 10 miles of Knowlton; the largest was 1.5 in on May 22, 2014. The most recent was September 7, 2023.
That is fewer than most places in the state on this site (median 11 days).
At the county level, Knowlton shares Warren County’s record of 10 storm disaster declarations since 2006, the newest DR-4725 (Severe Storm and Flooding, August 2023). (OpenFEMA.)
Storm reports are what observers logged, not a measure of damage to any 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; 91% 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 | Simple roofs with long, unbroken slopes | A complete standing-seam system may go over the old roof (R908.3.1) |
| Slate | 75 years | Older houses; 27% here predate 1940 | Sound slate can be reused (R908.5); broken slate cannot |
| Flat roof: EPDM or TPO | 15 years | Additions and porch roofs | Coating is not a replacement |
New Jersey had 47,473 active home improvement registrations in October 2026; the one belonging to whoever quotes your roof in Knowlton should be on the contract (N.J.S.A. 56:8-144).
Contracts, deposits and the right to cancel: checking a roofing contractor. What moves the price: new roof cost in New Jersey.
No permit for a detached house. New Jersey treats a new covering on a detached one- or two-family house as ordinary maintenance: no permit, no notice (N.J.A.C. 5:23-2.7). In Knowlton, 91% of homes are detached. An attached house, or work on rafters and beams, is not covered.
By the Census Bureau’s American Community Survey (2020–2024), the median home in Knowlton was built in 1978, 53% of homes were built before 1980, 88% are owner-occupied.
Hail of 1 inch or larger was reported on 8 days within 10 miles of Knowlton from 2006 through 2025 (NOAA Storm Prediction Center). A report means hail fell nearby, not that a roof was damaged.
New Jersey had 47,473 active home improvement registrations in October 2026; the one belonging to whoever quotes your roof in Knowlton should be on the contract (N.J.S.A. 56:8-144).
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.