Roof replacement, repair and storm damage in all 3 jurisdictions we cover in Jefferson County, each with its own page: the local permit rule, the code edition it enforces and the building department's number. Of the county's 93,955 homes, 71% were built before 2000 — past the usual 25-year life of a roof — and the median year built is 1987.
We list a building official's name only where the jurisdiction publishes one — 1 of 3 here do. We list a permit answer only where the jurisdiction states one — 1 of 3 here do, and 0 of those clearly require a permit. Everything else is left blank on purpose.
Jefferson County, town by town
Each line is a summary of that town's own page.
Arnold — 8,982 homes, median built 1977, 2% before 1940; code: 2021 IRC; re-roof permit: not published; building official named (Brian M. Herr).
Festus — 5,539 homes, median built 1983, 9% before 1940; code edition not published; re-roof permit: not published; no official named.
Imperial — 1,960 homes, median built 1990, 4% before 1940; code: 2015 IRC; re-roof permit: no; no official named.
Homes across Jefferson County: the Census numbers
Built before 2000
71%
66,511 homes
Median year built
1987
3% built before 1940
Built 2000 or later
29%
27,444 homes
Owner-occupied
82%
80% detached houses
Jefferson County has 93,955 homes in the Census count, with a median year built of 1987. 3% were built before 1940, 41% before 1980 and 29% in 2000 or later; the single biggest decade was the 2000s, with 16,786 homes (18%). 80% of homes are single-family detached houses and 82% of occupied homes are owner-occupied; the count includes 8,423 mobile homes.
About 25 years is the usual working life of a roof, by the figure Missouri's insurance department publishes. On that yardstick, 66,511 homes across Jefferson County (71%) were built before 2000 and have outlived at least one roof, and 24,154 (26%) predate 1970. The 16,786 homes from the 2000s are where first replacements are coming up now.
Across the 3 places we cover here with their own Census figures, Festus has the oldest housing (9% before 1940) and Imperial the newest (35% built in 2000 or later). Arnold is the largest, at 8,982 homes, and Festus has the highest share of renters (42%), where the roof is more often a landlord's decision.
Figures: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates (tables B25001, B25003, B25024, B25034, B25035). Survey estimates carry margins of error, widest in the smallest places. Census table.
Hail reports in Jefferson County, 2016–2025
NOAA’s Storm Prediction Center logged 67 reports of hail 1 inch or larger in Jefferson County from 2016 through 2025, on 30 days. 16 were 1.75 inches or larger, and 3 of those reached 2 inches; the largest, 3 inches, fell on November 5, 2017. The busiest single day was March 14, 2025, with 23 reports.
Year
Reports
2016
10
2017
8
2018
1
2019
3
2020
2
2021
0
2022
3
2023
6
2024
10
2025
24
Counted within 5 miles of each town’s center, Arnold has the most reports (30) and Imperial the fewest (10). Each town’s own page lists its latest dates. Reports come from spotters and the public, so busier places log more of them.
Why the city matters more than the county
Missouri has no statewide residential building code: each city adopts an edition by ordinance, and in unincorporated areas the county's code applies. Across the 3 jurisdictions we cover in Jefferson County, that adds up to 2 different editions in force:
2021 IRC: Arnold
2015 IRC: Imperial
Festus publishes no edition we could read. Ask before work starts which one the roof will be inspected against.
The design figures are the same across the metro (115 mph ultimate design wind, 20 psf ground snow), so the local difference is the code edition and the permit route. What each figure does to a roof is in our St. Louis roofing code guide.
Common questions about roofing across Jefferson County
Do I need a permit to replace a roof in Jefferson County?
It depends on the city, not the county. Of the 3 jurisdictions we cover across Jefferson County, 1 exempts a like-for-like re-roof (Imperial); the other 2 publish no answer either way. Each city page says which applies and links the building department.
Which building codes are in force across Jefferson County?
Across Jefferson County the jurisdictions we cover enforce 2 different editions: the 2021 IRC in Arnold; the 2015 IRC in Imperial. 1 publishes no edition we could read. The edition in force is the one your roof is inspected against.
How old are the houses across Jefferson County?
The Census Bureau's 2020–2024 estimates put the median year built across Jefferson County at 1987, with 3% of its 93,955 homes built before 1940 and 29% in 2000 or later. 71% were built before 2000, so most have had at least one new roof already.
Does a roofer need a license in Jefferson County?
Missouri has no state roofing license; licensing and registration are set city by city. We found no published registration requirement among the cities we cover in Jefferson County, which is not the same as none, so ask the city before work starts.
Which Jefferson County jurisdictions name their building official?
1 of the 3 we cover publishes a name: Arnold. Where a name is published, it is on that city's page with the department's own number.
Town rules from each jurisdiction's own pages, researched 2026-09-09; housing, Census ACS 2020–2024; hail, NOAA Storm Prediction Center. Sources: data.census.gov · www.spc.noaa.gov · www.stlpr.org. Rules and staff change; check with the jurisdiction.
Free roof inspection
Roofing anywhere in Jefferson County
Free inspection, a written scope, and photos you keep either way.
