What a Full Roof Replacement Covers
Full Tear-Off to the Deck
Michigan's residential code is blunt about it: a roof replacement "shall include the removal of existing layers of roof coverings down to the roof deck" (R908.3). That's the line between a replacement and a re-cover. The crew strips shingles, felt and old metal until bare boards show, and only then does anyone know what the deck looks like. Whether a re-cover is allowed instead depends on how many layers are already there; the layer limit is explained on our asphalt shingle roofing page.
One exception saves work at the eaves. If the old roof has an ice barrier membrane stuck to the deck, the code lets it stay in place and be covered with a fresh layer of ice barrier. Self-adhered membrane rarely peels off clean, so scraping it usually means ruining the plywood under it.
On an older house we'd expect the tear-off to turn up something, whether it's a forgotten second layer or a patch of soft boards around a chimney. Budget for it before the dumpster arrives.
Roof Deck and Sheathing Replacement
Asphalt shingles have to be fastened to "solidly sheathed decks," and each nail has to reach at least 3/4 inch into the sheathing. Rotted, delaminated or springy boards can't hold a nail that deep, so they come out and new plywood or OSB goes in. Houses that were first roofed with cedar sometimes have spaced board sheathing with gaps between the planks. Shingles can't go straight onto that; it needs solid sheathing over or in place of it.
HomeGuide puts roof decking replacement at $2 to $5 per square foot installed. Nobody can price it exactly until the old roof is off, so the written estimate should name a price per sheet and say how many sheets, if any, are already included. It's the line we'd read twice.
Underlayment and Drip Edge
Underlayment covers the whole deck under the shingles. The code requires it to carry a label showing compliance with a named standard, such as ASTM D226 felt or ASTM D4869, so ask what's on the roll. Along the eaves, a self-adhering ice barrier goes down first; why Ann Arbor roofs need it, and how far up it runs, is on our ice dam removal page.
Drip edge is required at the eaves and rakes of every shingle roof. Pieces overlap at least 2 inches and are nailed no more than 12 inches apart. The order matters: at the eaves the underlayment laps over the drip edge, and along the rakes it tucks under. Get that backwards and water running down the felt ends up behind the metal. While the roof is open, the code also requires rusted, damaged or worn flashings, vents and edgings to be replaced instead of reused.
Partial and Section Replacement
Not every house needs the whole roof done at once. A south-facing slope that bakes all summer, a rear addition with its own roof plane, or a section crushed by a falling limb can be replaced alone. The replaced area still gets torn off to the deck and gets new underlayment and flashing where it meets the old roof.
Matching is the catch. Shingles fade, and a discontinued color won't match at all. In our opinion a partial job works best where the new section is its own plane, like a back slope or a porch roof, and looks patched when it's half of a front slope seen from the street. If the rest of the roof is close to the end of its life anyway, a full replacement in one visit usually costs less than two separate tear-offs a few years apart.
Choosing the New Roofing Material
If the new roof is asphalt, the product choices, from three-tab to Class 4 impact-rated shingles, are on our asphalt shingle roofing page. Sections too flat for shingles need a membrane instead; see flat roofing. Metal roofing and slate roof repair cover the other two common choices. In a historic district, switching materials needs city review first, which the slate page explains.
Why Ann Arbor homeowners call Ann Arbor Roofing Co.
- Written estimate, free of charge
- Shingle line, underlayment and ice barrier named in the price
- Deck repair priced per sheet before the tear-off
- One independent local roofer per request, not a call list
- No fee to the homeowner for the referral
How Much Does a Roof Replacement Cost in Ann Arbor?
For an average-size house, national figures put an asphalt replacement around $9,600 to $10,800: Angi's 2026 average is $9,609 and HomeGuide's is $10,800. Larger and steeper Ann Arbor houses cost much more: in the 2025 Cost vs Value report, a 30-square (3,000 sq ft) asphalt tear-off in the Detroit area came to $33,692.
Quotes are written per square, meaning 100 square feet of roof surface, not floor area. HomeGuide's range is $300 to $600 per square, so a 2,000 square foot roof (20 squares) comes to roughly $6,000 to $12,000 before extras. Read the estimate for these lines:
Removal
HomeGuide lists removal of an old roof at $100 to $300 per square. A second layer means more labor and more dumpster weight.Decking
A per-sheet price, as above, at $2 to $5 per square foot installed in HomeGuide's figures.Flashing and vents
New step flashing, pipe boots and ridge vent should be listed, not assumed.Permit
Valuation-based in Ann Arbor (next section).
Resale won't pay the whole bill back. The same Cost vs Value report found a Detroit-area asphalt replacement recouped 67.8% of its cost when the house sold.
Do You Need a Permit to Replace a Roof in Ann Arbor?
Plan on one. Under Michigan's residential code, altering or repairing a house takes a permit unless the job is on the exempt list, and roofing isn't on it; and the City of Ann Arbor says home improvements need a building permit, applied for through its STREAM system. The contractor normally pulls it.
The fee follows the job's value: a $15 application fee, then $100 plus $10 per $1,000 of cost, plus 20% of that permit fee for plan review. On a $25,000 re-roof that works out to $15 + $350 + $70 = $435, by our arithmetic. A house in a historic district adds a $35 staff review. No city page names re-roofing as its own permit type, so if the numbers matter to your budget, the city's Building and Construction Services office can confirm which fees apply.
If only a few shingles or one flashing are failing, a replacement may be more than you need; see roof repair in Ann Arbor. After hail or wind, start with storm damage roof repair, which covers the insurance claim and how to check a contractor's Michigan licence.