Janesville, WI · Flat Roof

Flat Roof Contractors in Janesville, Wisconsin

Commercial or residential flat roof — compare local roofing companies. 22 local roofers listed.

Short answer: Flat and low-slope roofs in Janesville are usually TPO ($5.50–$9 a sq ft installed), EPDM ($4.50–$8) or modified bitumen ($3–$7); the membrane lasts 15–25 years, mostly decided by how well the drains are kept clear. In Janesville: 5.6 heavy-rain days a year (1 inch+). Ask any roofer for a license number and a certificate of insurance.

Get a free quote See Janesville in numbers
  • 5.6heavy-rain days a year (1 inch+)
  • 38.6 inrain a year
  • 3days a year at 90°F or hotter
  • 26%of homes are not single-family houses

How much life is left in my Janesville roof?

Typical lifespans are published ranges for each material; for a Janesville house, real life also depends on installation, attic ventilation and the weather Janesville gets.

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Flat and low-slope roofs in Janesville must be engineered and maintained for snow load — pooling meltwater under a heavy snowpack is the leading cause of membrane failure here, and drain clearing each fall is not optional. Common flat roof systems in Janesville include TPO (heat-welded, energy-efficient), EPDM (durable rubber membrane), and modified bitumen — each with different cost, longevity, and maintenance profiles worth discussing with a local contractor.

Janesville in numbers

Public records for Janesville and its county, not estimates. Each figure shows its source.

  • #48of 209Janesville ranks #48 of the 209 cities we cover for freeze-thaw days.

Hail reports per year in the county

Hail events per year in the county, 2017 to 2026* 3 2017 3 2018 2 2019 2 2020 4 2021 9 2022 2 2023 10 2024 18 2025 10 2026*
Hail events per year in the county, 2017 to 2026*
20173
20183
20192
20202
20214
20229
20232
202410
202518
2026*10

63 recorded events across 9 full years plus 2026 to June represented in the data, about 5.9 per represented full year. 2025 had the most events among represented full years: 18.

2026 covers only January to June: NOAA's file ends there, so it is not counted as the worst year or in the yearly average.

Source: NOAA hail events, county level · data as of 2017–2026*

Costliest storm day on record

Jun 22, 2024

6 reports that day (5 wind, 1 tornado); reported property damage $24,808,000; county FIPS 55105, 2014–June 2026

Source: NOAA Storm Events · data as of 2014–June 2026

When storms hit Janesville

Hail reports by month in the county, all years combined 0 Jan 1 Feb 5 Mar 23 Apr 10 May 7 Jun 10 Jul 12 Aug 5 Sep 1 Oct 0 Nov 0 Dec
Hail reports by month in the county, all years combined
Jan0
Feb1
Mar5
Apr23
May10
Jun7
Jul10
Aug12
Sep5
Oct1
Nov0
Dec0

Most hail reports come in April; the season runs March to September. Book inspections and repairs before that window, not after.

Source: NOAA Storm Events · data as of 2014–June 2026

Roofing trade around Janesville

  • 21 roofing companies with payroll in the county, employing about 55 people; 76% have fewer than 5 employees.
  • A roofer's median pay here is $63,310 a year (Janesville-Beloit, WI Metro Area).
Source: Census CBP · data as of 2023 Source: BLS OEWS, roofers · data as of May 2025

Janesville storm record: Rock County

What the National Weather Service logged in Rock County in 2014–2026. County level, because storm reports are filed by county, not by city limits.

  • 1853Founded
  • 853 ft (260 m)Elevation

Where hail of 1 inch or more was reported in Rock County

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  • 431 to 1.74 in
  • 141.75 to 2.74 in, golf ball to tennis ball
  • 32.75 in and up, baseball

Largest plotted stone: 2.75 in. Bigger dots are bigger stones.

60 reports of 1 inch or larger have coordinates. Each dot is a reported location, not a storm path.

Sources: NOAA, Census county outline

Biggest hail days

DateLargest hailReports that dayWhere it was reported
April 18, 2025 2.75 in, about the size of a baseball 11 Evansville
July 23, 2022 2 in, about the size of a hen egg 5 Mallwood
April 17, 2026 2 in, about the size of a hen egg 4 Beloit
“Numerous reports of wind damage were received. Destructive, large hail and flash flooding also occurred.”
National Weather Service report, July 23, 2022
Source: NOAA Storm Events Database · data as of 2014–2026

Last big hail on record

April 17, 2026

Hail of 1.75 inches (golf ball) or larger fell on 4 days in 2014–2026. Our records end where NOAA's do, so a newer storm may not be listed yet.

Strongest tornado

EF2 · February 8, 2024

It stayed on the ground for 13.71 miles and was up to 750 yards wide. Beginning section of the second tornado to ever occur in February in Wisconsin. Storm chaser/spotter/public videos show the tornado beginning around 5:39pm south of Evansville.

Strongest thunderstorm gust

85 mph · June 10, 2026

Trained spotter estimates 85 MPH wind gusts from observations and home weather station.

What it means for flat roof

Flat and low-slope roofs hold hail on the surface instead of letting it bounce. With 2.75-inch hail on record in Rock County, ask what membrane and cover board the contractor specifies.

Storm data: NOAA Storm Events (public domain). City facts: Wikidata (CC0).

What it costs in Janesville

Asphalt-shingle re-roof, 2,000 sq ft home, adjusted for Janesville labor and material prices. Your quote depends on roof size, pitch and scope.

That typical price is about 5.1% of the median Janesville home value ($209,700).

Source: Census ACS (Janesville city) · data as of 2019–2023

Full Janesville cost guide by material →

What Janesville's climate means for flat roof

  • Flat and low-slope roofs in Janesville must be engineered for snow load and kept drained — ponding under a melting snowpack is the top failure point here.
  • Janesville's freeze-thaw cycling works open membrane seams and flashing laps — heat-welded TPO seams outlast taped or adhered ones in this climate.

Roofers in Janesville, WI

22 listed, first 20 shown. Roofers we verified against a public registry come first.

This list covers roofing companies generally. Confirm flat roof experience, materials, insurance and current availability with each company. A Verified badge refers to the registry check, not a confirmed specialty.

Flat Roof in Janesville: questions

How do I find a flat roof company in Janesville?
PickARoofer lists roofing companies serving Janesville, WI. This is a general roofing directory; confirm flat roof experience and availability with each company. A Verified badge describes a separate registry check, not a confirmed service specialty or insurance check. Confirm scope, insurance and availability directly. Requests go to one contractor at a time, with up to three attempts; a response or start date is not guaranteed. Free for homeowners.
Should I repair or fully re-roof in Janesville?
Ask a roofer to document the damage and compare a written repair scope with a replacement estimate. Roof condition, remaining life, materials and the extent of damage affect the decision. Confirm any inspection fee before booking.
When is hail season in Janesville?
April is the worst month: 31% of the 74 hail reports NOAA holds for the county came then. Reports run from March to September. Book the inspection before March, while crews still have open dates.
How big does hail get near Janesville?
The largest hail NOAA logged near Janesville measured 2.75 inches, about the size of a baseball. Hail of an inch or more fell on 25 days in the same record. The biggest day was April 18, 2025, with 11 reports. The National Weather Service calls hail of 1 inch or larger severe; the bigger the stone, the more likely it is to crack a shingle.
How old are the homes in Janesville, and does it matter for the roof?
The median home in Janesville was built in 1972, and 63.2% of homes date from before 1980 (Census ACS). A roof on a home that old has often been re-covered at least once, so ask the roofer whether there is a second layer underneath: it changes the tear-off cost. The area sees about 95 freeze-thaw days a year, which loosens flashing and sealant.
What does roofing cost in Janesville?
For an average 2,000 sq ft home we model asphalt-shingle re-roof at $6,580 to $14,570 in Janesville, around $10,600 in the middle. That is about 5.1% of the median home value of $209,700. Your quote moves with roof size, pitch and how many layers come off.
How many roofing companies work around Janesville?
The Census Bureau counts 21 roofing companies with payroll in Rock County, employing about 55 people. 76.2% of them have fewer than five employees, so most quotes come from owner-run crews. A roofer's median pay is $63,310 a year (BLS).
How do I maintain a flat roof through Janesville's winters?
Flat roof maintenance in Janesville centers on drainage: clear drains and scuppers each fall before the first snow. Ponding meltwater under a deep snowpack is the leading cause of membrane failure here — water weighs 5.2 pounds per square foot per inch of depth, and even a few inches of standing water adds significant unplanned load. After heavy snow events, a professional roof rake or heating cables at the drain area prevent the most dangerous pooling. Annual spring inspections after snowmelt catch seam and flashing damage before it compounds.
What is the difference between TPO, EPDM, and modified bitumen for Janesville properties?
TPO (thermoplastic polyolefin) uses heat-welded seams and a white reflective surface — the current industry standard for new commercial and residential flat roofs, best for energy efficiency. EPDM (ethylene propylene diene monomer) is a rubber membrane installed with taped or adhesive seams — very durable and forgiving, widely used on residential flat roofs for decades. Modified bitumen is a reinforced asphalt sheet applied by torch or cold adhesive — economical and familiar to many local Janesville contractors, though it runs warmer than TPO and may require more frequent coating. Cost, pitch, and building type typically dictate the right choice — a Janesville flat-roof specialist can walk you through the tradeoffs for your specific structure.
Do I need a permit for flat roof in Wisconsin?
Permit requirements depend on the property, scope of work and local jurisdiction. Check with the city or county building department and confirm who will obtain any required permit before work starts.

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Figures above: NOAA Storm Events Database (hail, wind, tornado; county of the city, 2014–2026), U.S. Census Bureau American Community Survey 5-year estimates (housing), NASA POWER (temperature and rain, 2014–2023). Prices: our published price method. How we collect data.