Three shingle materials share the roofs of southern Maine: asphalt, cedar and slate. This page compares them on the points the code and the towns care about: slope, deck, nailing, fire, roof-overs and what historic boards allow.
Kennebunk's historic district guidelines describe a street most towns here would recognize: roofs mostly asphalt shingle in black, gray, brown and green, a few original slate roofs left, and some new wood shingle roofs. York keeps many Gilded Age summer houses in the Shingle style, Kennebunkport's Cape Arundel colony is lined with shingle-style cottages, and Phippsburg's older villages hold mid-1800s Greek Revival capes.
Each material has its own rules in the 2021 code Maine enforces, and some towns add their own, especially for wood and in historic districts. Asphalt is the common choice; cedar and slate are heavier, wear differently and answer to different fire and historic rules. The drawing shows the layers under any shingle roof; the sections below compare the materials.
Most new roofs here are asphalt, in two broad kinds: flat three-tab shingles and thicker laminated, or architectural, shingles with a layered look. What the code asks of them:
For service life, HUD expects about 20 years from asphalt laid on bare deck and about 15 from a layer laid over another, while Maine's insurance bureau rounds a roof of any kind to 25. The maker's printed nailing pattern, often more than four nails, is what its wind rating and warranty depend on, so it is worth asking whether a quote follows it.
Wood roofs come in two forms. Shingles are sawn smooth and thin at the top; shakes are split, with a rougher face. The code treats them a little differently:
Some towns limit wood for fire safety. Cornish and Parsonsfield require roof coverings rated at least Class C for fire; Parsonsfield also bars untreated wood shingles. Richmond's Village District rules, enforced by the fire chief, move wood roofs to fire-resistive shingles or other roofing once they need redoing. In York's historic districts, by contrast, the commission encourages wood shingle roofs but says rough wood shakes should not be used.
Slate is the heaviest of the three, and the rules follow from that:
Historic boards here lean toward keeping it. Kennebunk's guidelines encourage maintaining and repairing slate, and where it truly has to go, suggest a concrete slate, or asphalt in a color close to the original. York's want slate fixed, or matched piece for piece, and say synthetic slate should not be used. A slate roof with sound stone but failing nails or flashing is often a repair job, not a replacement; see roof repair.
| Material | Lowest slope | Deck | Roof-over allowed? |
|---|---|---|---|
| Asphalt shingles | 2 in 12 (doubled underlayment to 4 in 12) | Solid | Once, over sound asphalt; never over two layers |
| Wood shingles | 3 in 12 | Solid or spaced | New roofing over wood needs a fire-barrier layer if it leaves a hidden space |
| Wood shakes | 3 in 12 | Solid or spaced boards, 1x4 or wider | Topsham's checklist lists shake among roofs to strip first |
| Slate | 4 in 12 | Solid | No |
| Metal shingles | 3 in 12 | Solid or closely fitted | See metal roofing |
Weight is the line the table does not show. Moving from asphalt to slate adds load the rafters were not necessarily built for, and a recover adds a layer too; the frame has to carry it, a point on Topsham's re-roof checklist.
A like-for-like re-roof is maintenance almost everywhere. Changing the color or the material is where review comes in:
Outside these districts, color and material are your call, within the code and any fire rule your town sets.
Two quotes for "architectural shingles" can describe very different roofs. A useful written quote names:
On a job over $3,000, Maine's Home Construction Contracts Act also asks for a general description of the work and materials in the contract itself, so this list belongs on paper. Roof replacement covers the rest of the contract rules.
There is no single answer. Asphalt is the common choice; cedar suits many older capes and shingle-style houses where the town allows wood; slate is heavy and needs a 4 in 12 slope and a solid deck. The slope, the frame, the town's fire rules and any historic district narrow the choice.
The code's floor is four per strip shingle, but it defers to the shingle maker when the maker asks for more, and the maker's wind rating and warranty depend on its printed pattern. Ask a roofer what that pattern is for the shingle quoted.
Usually, at a slope of 3 in 12 or more, but check the town. Parsonsfield bars untreated wood shingles and wants at least a Class C fire rating, Cornish wants Class C, and Richmond's village rules call for wood roofs to be replaced with fire-resistive roofing. York's historic guidelines, on the other hand, favor wood shingles.
Outside a historic district, yes. Inside one, it depends: Kennebunk's guidelines will take a concrete slate or a near-matching asphalt once the slate cannot be saved, while York's want slate fixed or replaced with slate.
Only in some places. In Kennebunk's historic district a color change needs a certificate, York treats a new roofing color as a minor change needing one, and South Berwick wants roofing that matches its neighbors. Elsewhere, color is up to you.
Roof shingles 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:
Sources: MUBEC residential code (2021 IRC with Maine amendments), Chapter 9: R905.2, R905.4, R905.6, R905.7, R905.8, R908.3.1.1, R908.4, R908.5 (UpCodes copy) · Town of Topsham, residential re-roof inspection checklist · Town of Topsham, 2021 design criteria with Table R301.2 footnote h · Town of Kennebunk, historic district guidelines (roofs) · Town of York, Historic District Commission guidelines · Town of South Berwick, historic district code (Chapter 84) · Town of Freeport, Design Review ordinance · Town of Standish, Historic Preservation Commission · Town of Cornish, Land Use Ordinance (roof fire rating) · Town of Parsonsfield, Code Enforcement (building code section) · Town of Richmond, Land Use Ordinance Article 4 (Village District) · HUD, Residential Rehabilitation Inspection Guide · Maine Bureau of Insurance, Post-Disaster Claims Guide · 10 M.R.S. 1487, home construction contracts · Kennebunkport, York and Phippsburg house styles (pack place research). Codes, programs and prices change; confirm the current rule with your city before you rely on it.
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