Roof Replacement in Portland, ME | Snow, Ice & Permits

Two government yardsticks frame the question. A roof usually lasts about 25 years by the Maine Bureau of Insurance's reckoning, and HUD's guide for inspecting older homes allows roughly 20 for a first layer of asphalt shingles. Plenty of houses here have outlived several roofs: Census estimates for 2020–2024 date 16,740 of Portland's 36,559 homes, 46 percent, before 1940, and 57 percent of Bath's. Old houses often hide an older roof under the current one, and boards instead of plywood.

The rules for the roof itself match in every town. Maine has one code, built on the 2021 International Residential Code, and Maine left its roof chapter alone. What moves is whether your town wants a permit, whether a preservation board reviews the work, and the snow figure for your lot. The roofing code guide has the background.

Signs a roof here has reached the end

A single leak is a repair. A roof is ready to replace when the wear is spread across it. What gets a close look:

Age. Past 20 to 25 years, the two government rules of thumb above, a shingle roof is on borrowed time even if it still sheds a summer rain.
Granules and edges. Bald patches, curled or cracked tabs, and shingles that have lost their seal on several slopes.
Winter leaks that return. A stain near an outside wall that grows every thaw usually means water backing up behind ice at the eave; see ice dams & roof snow.
A soft deck. Sheathing that gives underfoot cannot hold a nail, and it should be found before a price is written.
Layers. Count them at the edge or in the attic. Two or more means the next roof has to start from the wood.

If what turns up is local damage on a roof with life left, the answer is roof repair, and the report says so.

What Maine's code says has to come off

Section R908.3 of the 2021 code defines a roof replacement as stripping every existing layer down to the deck. One thing may stay: an ice barrier membrane that is bonded to the deck, as long as a new one goes over it.

Laying new roofing over old, a recover, is not allowed in three situations listed in R908.3.1.1:

the old roofing is soaked or so worn out that it is no sound base;
the old roofing is slate, clay or cement tile, or asbestos-cement tile;
there are already two or more roof coverings of any kind on the deck.

Topsham's own re-roof checklist, written to the 2021 code with Maine's amendments, repeats the list and adds wood shake to the second line. It also reminds owners of two things a recover brings: going over wood shingles can leave a combustible hidden space that has to be covered with gypsum board or another approved layer (R908.4), and the frame has to be able to carry the added weight. Rusted or damaged flashings, vents and edge metal may not be reused (R908.5).

Maine's Department of Environmental Protection, in a flyer posted by Waterboro's code office, says asphalt roofing taken off without sanding, grinding or a mechanical roof cutter does not need a licensed asbestos contractor.

Two workers using roofing shovels to strip worn asphalt shingles off a house roof

The layers that go back on, from the deck up

The drawing shows the layers of a new shingle roof. What the 2021 code asks of the main ones, and what a written quote should say about each:

Deck. Asphalt shingles need a solid deck (R905.2.1). Old board decks with gaps get sheathed over or replaced, priced as their own line.
Drip edge. Required at both eaves and rakes on a shingle roof (R905.2.8.5), lapped at least 2 inches and nailed no more than 12 inches apart. Maine made no change here.
Ice barrier. A self-adhering membrane, or two layers of underlayment cemented together, at the eaves wherever the town's design table answers Yes. The next section explains how far it runs.
Underlayment. Over the rest of the deck, by the code's tables (R905.1.1). On slopes from 2:12 up to 4:12, shingles need a double layer (R905.2.2).
Shingles. At least four nails per strip shingle, or more where the shingle maker asks for more (R905.2.6). The roof shingles page compares asphalt, cedar and slate.
Flashing. Rebuilt to the maker's instructions (R908.6). A chimney that measures over 30 inches side to side gets a small peaked saddle on its uphill face (R903.2.2).
Vents. Intake low, exhaust at the ridge, sized by the code's ratio. Roof ventilation has the arithmetic.

Ridge vent — exhaust at the peak, matched to intake at the eaves so the attic can breathe.
Architectural shingles — nailed to the shingle maker's printed pattern, which can ask for more nails than the code minimum.
Starter strip — the sealed first course at the eaves, so wind cannot get under the edge.
Synthetic underlayment — the second line of defense if water ever gets past a shingle.
Ice-and-water shield — self-sealing membrane at the eaves and valleys, where ice dams back water up.
Drip edge — metal along the edge that steers water into the gutter, not behind it.
Roof deck — walked board by board; soft or rotten sheathing is replaced first.
Rafters — the frame the whole roof sits on.

How far the ice barrier has to reach

Whether the barrier is required at all is a line in each town's copy of the design table, Table R301.2. The towns that print that line here, Cape Elizabeth, Topsham and Biddeford, all mark it Yes, as the code expects wherever ice dams have done damage before.

Where it is Yes, Section R905.1.2 sets the reach. The membrane starts at the bottom edge of the roof and continues upward until it is 24 inches or more past the line of the outside wall, measured inward. Because that is counted from the wall and not the drip edge, a deep overhang needs a wider strip. On a pitch of 8 in 12 or more, it also has to cover no less than three feet of roof measured up the slope from the edge. Detached outbuildings with no heated space are the one exception.

Ask where the membrane stops. A quote that just says "ice and water shield" has not told you how many courses run up from the eave, whether the valleys get it, or what happens at a low dormer. Get the widths in writing before the tear-off.

The barrier keeps meltwater out of the house; it does not stop the dam from forming. That takes air sealing and insulation in the attic, the subject of the ice dams page.

Snow load and the frame under the shingles

Maine publishes no town-by-town snow table. Since November 2025 the state's code office has designers type the street address into the ASCE Hazard Tool and read the ASCE 7-16 snow figure. When the tool answers "case study required", they take the 7-22 figure times 0.70, with 100 pounds per square foot as the floor.

Towns that print a figure show how much it moves: Cape Elizabeth's table says 50 psf; Yarmouth, Topsham, Biddeford and Westbrook say 60; Raymond says 70. Gorham's code handout asks every new building to carry a total roof load of 70 psf, split into 42 live and 28 dead.

A like-for-like re-roof does not redesign the frame, but three things put it back in play:

a heavier covering, such as slate replacing asphalt;
a recover, which adds a layer of weight the rafters have to hold;
cracked rafters, sagging ridges or a soft section found during the tear-off.

Structural roof work needs a building permit in nearly every town, even those that exempt plain re-roofing. Bath and Brunswick add that engineered trusses or lumber may need paperwork from a design professional.

Does a re-roof need a permit in your town?

Maine changed the code so that a permit is needed where a town's ordinance requires one, which is why neighboring towns answer differently. A sample from the town research:

Town	Plain re-roof, no structural change	What changes the answer
Portland	No building permit	Structural work; a designated historic property
Hollis	None with the same material	Replacing or adding plywood, framing or other underlying material
York	Permit; its weekly lists include re-roofs	Fee $10 per $1,000 of cost, $50 minimum
Richmond	Its own $20 re-roofing permit	The form asks the layers on now and strip or roof-over
Kittery	A maintenance permit application	The town's own example: a $15,000 roof pays $85
South Portland	Ask first; its FAQ says a permit is "very likely"	Email the code office with the address

Eliot, Brunswick, Kennebunkport, Raymond, Buxton and Lyman also exempt a plain re-roof, several with a request to check with the code officer first. Every town page under roofing by town carries its own answer.

Historic districts: when a board reviews the roof

Most historic rules here turn on two questions: can the roof be seen from the street, and is the new material the same as the old? Replacing in kind is usually maintenance. A change of material or color is not.

Portland: on a designated property, visible roofing is on the city's list of work that needs preservation approval first, and staff handle most of those reviews.
Kennebunk: the district guidelines want a certificate before a roof changes color or material, and they favor keeping and repairing slate.
York: a roofing material of another kind, color or texture is a minor change that still needs a certificate; altering a roofline is a major one.
Freeport: in the two design review districts, wood shingles, architectural asphalt, slate and copper are on the exempt list, while other visible materials go to the board.
Brunswick: the Village Review Board's guidelines ask that a historic roof be photographed for the Pejepscot Historical Society before the work.

The contract, the price, and what moves it

Maine's Home Construction Contracts Act reaches repair work on a home of up to three units. Once the price passes $3,000, the deal has to be on paper, signed by you and the roofer, and each of you keeps a copy before anyone starts. The paper must carry estimated start and substantial-completion dates, the total price, what work and materials are included, the warranty statement the law prescribes, and a payment plan that asks for no more than a third of the price up front. Later changes go on a signed change order that shows the old and the new price. If the sale began with a salesman at your door or an unrequested phone call, you also get three full business days to back out by mailed notice, and nothing gets attached to the house until they pass.

No regional price figure is quoted here. What moves the number:

roof area, pitch, and the count of dormers, valleys and chimneys;
how many layers come off and how much deck is replaced;
the covering: asphalt, cedar, metal or slate;
how far the ice barrier runs, and any vent fixes;
access, island homes included, and the permit fee where one applies.

Common questions about roof replacement in Portland

Can a new roof go over my old one in Maine?

Sometimes, but rarely on an older house. The code bars it over roofing that is wet through or rotten, over slate and tile, and over a deck that already carries two coverings. Even a legal roof-over hides the deck and adds weight, so most replacements here start from bare wood.

Does Portland require a permit for a new roof?

Not for re-shingling alone. Portland's permit guidance exempts a re-roof that makes no structural change. Replacing rafters or sheathing in a structural way needs a building permit, and a designated historic property can need preservation approval for visible roofing. Other towns differ; York and Richmond, for example, issue permits for re-roofs.

How long does a roof last in Maine?

Maine's Bureau of Insurance works with about 25 years in its claims guide. For asphalt, HUD's guide allows roughly 20 years on a first layer and 15 on a second. Snow, ice dams, attic heat and slope all move the real number for a given house.

How far up the roof does the ice barrier have to go?

Where the town's table says Yes, from the bottom edge until it is two feet or more inside the outside wall, measured inward, so a wide overhang needs a wider strip. On a pitch of 8 in 12 or more it also has to cover three feet or more of roof along the slope.

What snow load does my roof have to carry?

It depends on the address. Maine's code office has designers take the ground snow load for the exact site from the ASCE Hazard Tool. The towns here that publish a figure give 50 to 70 pounds per square foot, and inland and higher sites can need more.

How much can a roofer ask for up front?

On a home repair contract over $3,000, Maine law caps the down payment at one-third of the total price, and the contract has to be written and signed by both sides before work begins. You and the contractor can only agree to set that limit aside after you have been told about the right.

Where we work

Roof replacement across greater Portland and southern Maine, from Casco Bay and the York County coast to the Sebago Lake towns. Each city has its own page with the permit rule and code edition that apply there: