A standing seam metal roof is a good roof for Cape Cod when it is specified for the Cape: aluminum panels within sight of salt water, concealed clips spaced for wind uplift at the eaves and rakes, high temperature underlayment across the whole deck, and snow guards wherever the roof sheds onto a door, a walk or a deck. Done that way it outlasts two asphalt roofs and shrugs off a nor’easter. Done the way it is done inland, with steel panels, standard clip spacing and no snow management, it rusts at the cut edges, hums in the wind and drops a slab of snow on the front step in February.
Coast Carpentry Home Improvement installs standing seam metal roofing on Cape Cod homes from Falmouth to Yarmouth, alongside asphalt shingle, red cedar and low slope roofing. We are based at 14 Parker Rd, Unit A in Osterville, and Fagner Rodrigues, who holds the Massachusetts Construction Supervisor license that every Coast job runs under, writes the panel and clip spec for each one. This is what we specify, what we have seen fail, and when we tell a homeowner to put shingles on instead.
Key takeaways
- Within a mile of salt water we specify aluminum standing seam panels, not coated steel. Steel’s cut edges and scratches rust first, and on the Cape the salt finds them within a few seasons.
- Wind uplift is the design load on Cape Cod. A standing seam roof holds through concealed clips screwed to the deck, and clip spacing tightens at the eaves, rakes and corners where the suction is highest.
- Metal sheds snow in slabs. Snow guards go over every door, walkway, deck and gutter run, and the gutters get brackets rated for the load, or the first thaw rips them off.
- On an old Cape, the deck matters as much as the panel. Wavy plank sheathing shows through metal, so many older roofs get re-sheathed and a high temperature ice and water membrane before any panel goes down.
- Coast Carpentry Home Improvement installs standing seam metal roofing across Barnstable County and will say when shingles are the better call: a Route 6A elevation in the Old King’s Highway district, a roof cut up with hips and dormers, or a house you plan to sell soon.
Is a standing seam metal roof a good choice on Cape Cod?
Standing seam means the panels run from eave to ridge and join at raised seams, with every fastener hidden under the seam. That is the whole appeal on the coast. An exposed fastener metal roof, the kind on barns and sheds, has thousands of gasketed screws through the face of the panel, and every one of them is a future leak once the gasket dries out. Standing seam has none.
The Cape adds two things most metal roofs never see: salt in the air year round and wind that comes off open water with nothing to slow it down. A spec that works in Worcester County can fail here. The rest of this guide is the list of things we change.
Aluminum or steel: which standing seam panel belongs near salt water?
Most standing seam sold in New England is coated steel, 24 gauge, with a factory finish. On the Cape we spec .032 inch aluminum with the same class of factory finish, and here is why. Every panel has two cut edges and every trim piece has more. On steel, the coating stops at the cut and the bare metal underneath is where rust starts, creeping back under the finish. Within sight of Nantucket Sound or Cape Cod Bay we have seen that happen in a few seasons. Aluminum has no iron in it to rust.
Aluminum has trade offs we plan around. It expands and contracts more than steel, so the clips must allow movement and the panels need a fixed point at the ridge or the eave, never both. It is softer, so it dents under a dropped tool and shows more oil canning, the slight waviness you see across a flat panel in low sun. Ordering panels with striations or a pencil rib takes most of that away. Read the finish warranty before you sign anything: the good ones name coastal exposure and say what they cover within a stated distance of salt water.
How does a standing seam roof hold up in Cape Cod wind?
Wind does not push a roof down. It pulls it up, and it pulls hardest along the perimeter and at the corners. The state building code puts Cape Cod in its highest wind zones, and a permit set should show a panel system with a tested uplift rating. Standing seam systems are tested to a standard called ASTM E1592, and the manufacturer’s tables tell us how close the clips need to be for a given wind pressure. We run the edge zones tighter than the field, every time.
The seam matters too. A snap lock panel clicks together by hand and holds well on a protected lot. A mechanically seamed panel is crimped shut with a seaming tool after installation, folding the two edges into one locked seam. On a bluff in Falmouth, on the shore in West Dennis, or anywhere a nor’easter hits broadside, we spec the mechanical seam. It is more labor and it is the one that stays on.
What underlayment and ventilation does a metal roof need on an old Cape?
A metal roof is only as flat as the deck beneath it. Shingles hide a wavy deck. Metal shows every hump and every sag between rafters, and a panel laid over cupped boards will oil can badly and can rub through its own finish at the high spots. On the Capes and half Capes built before the war, with board sheathing that has shrunk, we tear off, re-nail or sister the rafters where they need it, and lay new plywood. It adds a day or two and it is the difference between a roof that looks right for forty years and one that looks wrong on day one.
Underlayment on the Cape is a full coverage, high temperature, self adhering membrane. The standard ice and water shield most roofers carry is rated for a shingle roof; under dark metal in full sun it can soften and bleed at the laps. The high temperature version holds up. Full coverage matters because the seams and the penetrations are the only places water can get in, and when a wind driven rain pushes water up under a seam, the membrane is the second line.
Ventilation is the ice dam fix. A metal roof does not stop ice dams by itself; a warm attic melts snow from below, it refreezes at the cold eave, and water backs up under the panels. A continuous soffit intake and a ridge vent, with the insulation pulled back from the eaves so air can move, keeps the whole roof deck cold. We covered what an ice dam does to a roof in our ice dam guide; the cure is the same under metal as under shingles.
What about snow, ice and the people walking under the eave?
The slab is the part people do not expect. A foot of wet snow sliding off a two story roof lands with real force, enough to tear a gutter off, crush a railing, or hurt whoever is on the step. The fix has to be planned, not added later: seam clamped snow guards, in rows, placed by the manufacturer’s layout for the roof’s pitch and panel length. No holes through the panel; the clamps grip the seam.
The slab that comes off a metal roof hits the gutter first. We hang gutters on a metal roof with heavy brackets at close spacing and set the front edge of the gutter below the line of the roof plane, so sliding snow clears it. Our gutter installation page covers the hardware we use on Cape homes.
How do skylights, chimneys and dormers get flashed into a metal roof?
Penetrations are where metal roofs leak, and almost always because somebody flashed them like a shingle roof. Metal panels are continuous, so the flashing has to be formed to lock into the panel and the seam, with hems and closures, and every joint sealed with a sealant made for the finish. A chimney on the uphill side of a roof needs a cricket, a small peaked saddle, so water and snow split around it instead of piling against the brick. The old Capes with a center chimney and a shed dormer on the back, which describes half the houses in Sandwich village, are exactly where this work is done right or done twice.
If the roof is getting a new dormer or new skylights at the same time, we frame the curbs to suit the panel layout so seams land clear of the openings.
Where does metal suit a Cape house, and where does the historic district push back?
A lot of the metal we put on Cape houses is partial. A standing seam porch roof under a shingled main roof is a classic New England combination, and it solves a real problem, because a low pitched porch is where shingles fail first. A shed dormer on the back of a Cape, a mudroom ell, a breezeway, a garage: all of these take metal well and most of them are out of sight from the street. The photo at the top of this guide shows the whole house version on a shingle style home, with the dormer, a skylight and two chimneys flashed into the panels.
The north side of Barnstable, Sandwich, Yarmouth Port, Dennis, Brewster and Orleans along Route 6A sits in the Old King’s Highway district. The committee in each town reviews exterior changes visible from a public way, and roofing material is one of them. A standing seam roof on a rear ell or a side that cannot be seen from 6A is an easy case; a bronze metal roof on the front of an eighteenth century Cape is not. We draw the elevations for the review and tell you before you fall in love with the sample. The Barnstable Old King’s Highway Committee page is a good place to see what they look at.
Mechanically seamed or snap lock, and how long can the panels be?
| Decision | Snap lock standing seam | Mechanically seamed standing seam |
|---|---|---|
| How the seam closes | Panel edges click together by hand over the clip | A seaming tool folds the edges into one locked seam after the panels are clipped down |
| Minimum pitch | About 3 in 12 | Down near 1 in 12 with in seam sealant; flatter than that is membrane work |
| Wind exposure | Protected lots, inland villages | Shorefront, bluffs, open water exposure, any roof a nor’easter hits broadside |
| Labor | Faster, less specialty tooling | Slower, every seam is run with the tool |
| Best Cape uses | Porch roofs, dormers, garages, steeper main roofs off the water | Low slope additions, whole roofs on exposed sites, anything facing the Sound or the Bay |
Panel length is a question we get. Standing seam panels for a house are roll formed to the exact rafter length, either at the shop or from a portable roll former on the site, so there are no end laps on the roof. The practical limits are handling a long panel in wind and the thermal movement of the metal, which is why a long aluminum panel is fixed at one end and free to slide on its clips at the other. A thirty foot panel on a Cape roof is routine.
Low slope is where this decision gets serious. A roof under 3 in 12 cannot take a snap lock panel, and a roof flatter than about 1 in 12 should not take standing seam at all. That is a membrane roof, which we also install, and our Cape Cod roof guide on repairing versus replacing a roof walks through how we decide between the two.
What drives the cost of a standing seam metal roof on Cape Cod?
We do not publish prices because no two Cape roofs price the same. A simple gable on a ranch in Mashpee with a sound deck is one job. A center chimney Cape in Sandwich with two shed dormers, a bay window roof and plank sheathing that needs plywood is a different job on a similar footprint, and the difference is mostly in the trim and the deck, not the panels. Our post on what a new roof costs on Cape Cod explains how we build a roofing estimate; for a number on your house, ask us for a quote and we will measure it.
What a standing seam roof gives back is time. Where an asphalt roof on an exposed Cape site is tired in its twenties, a properly specified aluminum standing seam roof is still sound at twice that age, and that is the comparison that matters if you plan to stay.
When are asphalt shingles the better call?
We are a CertainTeed ShingleMaster installer and we put on far more shingle roofs than metal ones, so this is not a sales pitch for metal. A modern architectural shingle roof, installed with the membrane and ventilation described above, is a good thirty year roof on the Cape. On a cut up roof with a lot of hips and dormers, the trim on a metal roof becomes most of the job and most of the cost, and a shingle roof handles that geometry gracefully.
The historic district is the other hard stop. If the house faces 6A and the committee will not approve metal on the front, a mixed roof with shingles on the street side and standing seam on the rear ell is often the answer, and it is a combination that looks right on a Cape. Our guide to choosing a Cape Cod roofing contractor has the questions to ask any roofer about materials, and the Barnstable and Yarmouth roofing pages cover what we see village by village. The permit for either material comes through the town; the Barnstable Building Division page shows what the application looks like.
Thinking about a standing seam metal roof on Cape Cod?
Coast Carpentry Home Improvement installs standing seam metal, asphalt shingle, red cedar and low slope roofing on Cape Cod homes across Barnstable County, specified for salt air and wind. Start on our Cape Cod roofing page, then request a quote and we will look at the deck, the exposure and the historic district before we recommend a material. Cape homeowners say how it went on our reviews page.
Frequently asked questions about standing seam metal roofs on Cape Cod
Is a standing seam metal roof better than shingles?
For a long term owner on an exposed Cape Cod site, usually yes: it lasts far longer, sheds water and snow faster, and has no exposed fasteners to fail. Shingles are better on a cut up roof with many hips and dormers, on a front elevation the historic district reviews, and when the budget is better spent on the deck and ventilation. Both can be good roofs when they are installed for the Cape.
How long does a standing seam metal roof last on Cape Cod?
An aluminum standing seam roof with a factory finish, concealed clips and a high temperature membrane under it is a roof measured in decades, and the panel makers’ finish warranties typically run for decades as well. Steel panels near salt water last less because rust starts at the cut edges. The underlayment and the flashing details decide the real number more than the panel does.
How long can standing seam panels be?
As long as the rafter, because the panels are roll formed to the exact length at the shop or on site, with no end laps on the roof. The practical limits are handling a long panel in wind and allowing for thermal movement, so a long panel is fixed at one end and slides on its clips at the other. Most Cape Cod roofs run under thirty feet from ridge to eave, which is routine.
Is a metal roof loud in the rain?
Not on a house. Standing seam panels on a house sit over a solid plywood deck, a self adhering membrane and an insulated attic, and rain on that assembly sounds the same as rain on shingles. The drumming people remember comes from barns and sheds where the panels span open purlins with nothing beneath them.
Can a standing seam roof be installed over existing shingles?
It can be done, and on Cape Cod we almost never recommend it. Laying panels over old shingles traps moisture, hides a deck that may need work, and leaves the old roof’s humps and dips to show through the metal. On the Cape the shingles come off, the deck gets inspected and flattened, the high temperature membrane goes down over the whole roof, and the panels go on a surface we have seen.
We serve Cape Cod, Massachusetts
Coast Carpentry Home Improvement works across all 15 Cape Cod towns, from Bourne out to Provincetown. We do not take projects outside the Cape.
On the Cape and looking for an estimate? Call (508) 360-9658 or send us a message.
Need a roofer you can trust?
Coast Carpentry Home Group provides roofing services on Cape Cod. Licensed, insured, and local for 20+ years. Call (508) 360-9658 for a free estimate.