What flat roof repair involves
A repair visit starts with finding where water enters. On a low-slope roof that is often a wall edge, a pipe or vent, or a change in direction, the places where the code requires flashing (R903.2.1). The roofer then repairs or replaces that flashing or the covering around it. InterNACHI's chart names the common low-slope coverings as EPDM rubber, modified bitumen, built-up roofing and TPO, so ask which one you have.
What flat roof work costs in Michigan: estimates, not quotes
Our estimate for replacing a flat or low-slope roof in Michigan is $3,750 to $20,800 per roof, or $275 to $1,350 per square (100 square feet), installed. It is a model, not a quote: one published national range, adjusted for what Michigan roofers are paid, with a typical permit fee of $100 added to the per-roof figure. No Michigan roofing company we looked at published a price we could count, so none is shown.
The rows below the estimate are wages, which are pay and not price, and permit fees taken from city fee schedules.
| Item | Figure | What it is |
|---|---|---|
| Estimated range, not a quote | $3,750 to $20,800 per roof | Built from one national published range, adjusted by the Michigan roofer median wage ratio (1.07) plus a typical permit fee ($100). No Michigan roofing company price is shown, because none of the companies we looked at published a price we could count. |
| Estimated range per square, not a quote | $275 to $1,350 per square (100 square feet), installed | Built from one national published range, adjusted by the Michigan roofer median wage ratio (1.07). No Michigan roofing company price is shown, because none of the companies we looked at published a price we could count. |
| Roofer wage, Michigan median | $28.62 an hour (middle half of roofers: $23.02 to $37.56) | What Michigan roofers are paid (BLS May 2025, read through O*NET OnLine), not what you are charged. |
| Residential re-roofing permit, Grand Rapids | $66 | FY2027 fee schedule. |
| Re-roofing, Kalamazoo non-structural permit | $52 | 2026 fee schedule, read as flattened PDF text; confirm with the city. |
| Roof permit, East Lansing | $60 application, plus $140 | Residential, with rough and final inspections. |
How we estimate costs: the Estimated range row is a model, not a quote. It takes one published national range for this job (a cost guide from a third-party site that we have not verified and do not cite) and multiplies it by Michigan's roofer median wage ratio to the US (1.07, BLS May 2025 data read through O*NET OnLine) and adds a typical permit fee ($100). The wage and permit rows in the table are what roofing workers are paid and what a city's own schedule charges, and neither is a price. We have not collected quotes, and we found no Michigan roofing company that publishes a price we could count. Full method. Prices as of Oct 19, 2026.
Repair or replace a low-slope roof
We give no age threshold, because the only life table we found is a national trade chart. The repair or replace tool works through the questions that count.
- The leak traces to one flashing, vent or seam.
- Two or more applications of roofing are already on the deck, so nothing can go over them.
- The roofer shows wet or damaged decking in several places.
Why a slope below 2:12 changes the roofing system
Section R905.2.2 allows asphalt shingles only on slopes of 2:12 or greater, meaning 2 inches of rise over 12 inches of run, and from 2:12 up to 4:12 it requires double underlayment. Below 2:12 the roof needs a different system from shingles. LARA still lists the 2015 code as of Oct 19, 2026; a rule adopting the 2021 code is stayed by a court order and this may change, so check LARA before relying on it.
Michigan ground snow load by county, and what it does not tell you
Table R301.2(5) in Michigan's rules sets ground snow load by county in pounds per square foot of snow on the ground. A designer derives the load on a roof from it, so the table is not a capacity rating for your roof. Townships and cities can differ from their county, and your building department confirms the figure for your address. It runs from 20 pounds in Monroe, Lenawee and most of Wayne to 90 to 100 in Keweenaw; the Upper Peninsula and northwest Lower Peninsula commonly run 50 to 80.
| County | Ground snow load (pounds per square foot) | Cities or townships that differ |
|---|---|---|
| Wayne | 20 | Northville 25 |
| Oakland | 25 | |
| Macomb | 25 | |
| Washtenaw | 25 | Ann Arbor, Ypsilanti, Saline 20 |
| Genesee | 30 | Davison, Fenton, Grand Blanc, Linden 25 |
| Kent | 35 | |
| Ingham | 25 | Lansing, East Lansing 30 |
| Kalamazoo | 30 | Parchment, Alamo, Cooper, Oshtemo 35 |
| Calhoun | 25 | Battle Creek 30 |
| Saginaw | 35 | |
| Midland | 35 | |
| St. Clair | 25 | |
| Lenawee | 20 | |
| Marquette | 70 | |
| Houghton | 80 | |
| Keweenaw | 90 to 100 |
How long flat roof coverings last, from a trade chart
No government table gives flat roof life. InterNACHI, a home inspectors' trade association, prints 15 to 25 years for EPDM rubber, 20 for modified bitumen, 30 for built-up roofing and 7 to 20 for TPO. We have not confirmed the chart on its source page, and the figures are national, not Michigan-adjusted, so use them to compare materials, since they cannot set a replacement date.
Who may work on a flat roof and what replacement means
Roofing is a craft on the residential maintenance and alteration license, and work of $600 or more needs it; ask for the license number and check it with LARA. In the 2015 code a replacement means tear-off to the deck (R908.3), and a new covering over an old one is barred where two or more applications are already there, or where the roof is deteriorated.
Flat roof problems that count as an emergency
- Water is coming through a ceiling or light fixture.
- The ceiling or roof line is sagging under snow or water. Keep out of the room and call a roofing company or your building department.
- Meltwater is running inside along a wall.
- A stain that has not changed over several days, once photographed and dated.
- Debris on the roof in dry weather.
What to look for under a flat roof
- Look at ceilings under the flat section and outline each stain in pencil with the date.
- Check the attic or ceiling space, if there is one, for damp insulation and light at edges.
- Note when water appears: during rain, a thaw or after snow.
- Photograph the roof edge from the ground and do not climb up to shovel.
Permits on a flat roof job
Roofing is not on the state's R105.2 exemption list, and enforcement is local. Grand Rapids requires a residential building permit to re-roof; Kalamazoo handles it as a non-structural maintenance permit; East Lansing has a separate roof permit. Portage requires none to remove and replace shingles only, which says nothing about a membrane roof. Ask your building department.
Before any work starts, ask for the license number and check it with your state's licensing board.
- LARA M&A Contractor License Information Read Oct 19, 2026.
- MCL 339.2403 Read Oct 19, 2026.
- Mich. Admin. Code R. 408.30505 Work exempt from permit (LII) Read Oct 19, 2026.
- LARA Statewide Jurisdiction List (PDF), Rev. 10/6/2026 Read Oct 19, 2026.
A tool for this job
Repair or replace, and what it costs
Michigan has no rule that settles repair versus replace by age or by percent of roof, so this tool does not give a verdict on that. It sorts what to ask a roofing company for, using the Michigan code on layers, tear-off and ice barrier, and it estimates your roof area in roofing squares. Once you have the area, the page shows our modeled range for a replacement, which is an estimate and not a quote. It runs in your browser and asks for nothing.
Open the toolQuestions people ask
Can asphalt shingles go on a flat roof in Michigan?
Not below a 2:12 slope: Section R905.2.2 allows asphalt shingles only at 2:12 or greater, and from 2:12 to 4:12 it requires double underlayment. A flatter roof needs a different system.
How much snow can a Michigan flat roof hold?
The state table gives ground snow load by county, 20 to 100 pounds per square foot, but it is not a capacity rating for your roof. A designer derives the roof load. Ask your building department for your address.
How long does a flat roof last in Michigan?
InterNACHI's chart gives 15 to 25 years for EPDM, 20 for modified bitumen, 30 for built-up roofing and 7 to 20 for TPO. It is a national trade chart that we have not confirmed on its source page.
Does insurance cover a roof collapse from snow in Michigan?
DIFS says standard homeowners policies cover a building collapse caused by the weight of ice or snow. Coverage depends on the cause and your policy wording.
Does a flat roof repair need a permit in Michigan?
It depends on your city: roofing is not on the state's exemption list and enforcement is local. Grand Rapids charges $66 for a residential re-roofing permit.
What does flat roof repair cost in Michigan?
We have no sourced figure for a flat roof repair. Our estimate for replacing a flat or low-slope roof is $3,750 to $20,800 per roof, a model and not a quote. The nearest figure for a repair is the estimate on the roof repair page.
- BLS May 2025 wages for roofers (SOC 47-2181), Michigan, as shown by O*NET OnLine Read Oct 19, 2026. Confirm with the source before you rely on it.
- RooferMatch: how we estimate costs (editorial policy) Read Oct 19, 2026.
- Re-Roofing or Re-Siding of Existing Residential Building Permit - City of Grand Rapids Read Oct 19, 2026.
- City of Kalamazoo, Apply for Non-Structural Maintenance Permit (summary page; confirm with the city) + 2026 CPED Fee Schedule PDF Read Oct 19, 2026. Confirm with the source before you rely on it.
- City of East Lansing, Building Information (+ /1539/Fees, /2367/Projects-Not-Requiring-a-Permit, /1979/Apply-for-a-Permit-Online) Read Oct 19, 2026.
- 2015 IRC Chapter 9, R908.5-R908.6 Read Oct 19, 2026.
- LARA notice: 2021 Code Injunction, Residential Part 5 and Energy Part 10 (PDF) Read Oct 19, 2026.
- LARA BCC Code Books Read Oct 19, 2026.
- Mich. Admin. Code R. 408.30515 Ground snow loads (LII) Read Oct 19, 2026.
- DIFS: Winter Storms Read Oct 19, 2026.
- InterNACHI Estimated Life Expectancy Read Oct 19, 2026. Confirm with the source before you rely on it.
- City of Portage FAQ, Community Development - Building, Construction & Permits (same wording in the Tornado Response FAQs) Read Oct 19, 2026.
- Roof Tarping (Blue Roof) Safety, OSHA FactSheet Read Oct 19, 2026.