Copper Roofing Systems, From Seamed Pans to Zinc
Copper often goes on the small roofs people look at: a bay, a porch, a cupola or an entry. The right system depends on the shape and pitch of that roof.
Standing Seam Copper Panels
Copper standing seam is roll-formed or hand-formed pans with raised seams, held down by hidden cleats. HomeGuide says copper also comes as continuous rolls that the roofer crimps or solders on site, and it lists copper panel material at $14 to $22 per square foot before labor. Panels give the longest runs and the cleanest lines on a porch or portico roof.
Soldered Flat-Seam Copper
Flat-seam copper uses small rectangular pans with folded edges that lock together and are soldered shut, so the roof becomes one continuous copper skin. It suits curves, eyebrow roofs and cupola tops, where a long pan can't follow the shape. Soldering copper is its own skill. Ask to see a soldered seam the roofer has finished before you hire.
Copper Roofs on Bays, Dormers and Entries
These are the small accent roofs: a bay window, a pair of dormers, a front entry hood. HomeGuide puts a copper porch roof at about $2,000 to $6,000 nationally, depending on size. Because the roof is small, the trim, the flashing into the brick and the solder joints are most of the work.
Preformed Copper Shingles
Preformed copper shingles interlock like metal shingles, and the code allows a lighter 12-ounce copper for them. HomeGuide lists copper shingle material at $9 to $16 per square foot and says shingles are cheaper and easier to install than panels because less cutting is needed. It gives them a shorter life than copper panels: about 40 years, against 50 years and up.
Zinc Panels
Zinc roofing is seamed like copper and weathers to a matte gray. The 2018 IRC sets a minimum thickness of 0.027 inch of high-grade zinc alloy. VMZINC, a zinc maker, says the gray patina can form in about three years on a low-slope roof and can take more than ten years in sheltered spots. It also says zinc needs air on its underside. Plain zinc laid over a surface that traps moisture can form white rust from below, so the maker calls for a vented open-gap board deck or a zinc with a protective backside coating. HomeGuide puts installed zinc at $1,000 to $2,000 per square.
Why Jackson homeowners call Jackson Metal Roofing Pros
- One independent metal roofer gets your request, not a call list
- A free measure, deck check and written estimate
- Ask for panel system, gauge and paint finish in writing
- The roofing permit is part of the scope: ask who pulls it
- No charge to the property owner for the referral
Copper Roofing Weight, Thickness and Fasteners
Copper is sold by weight per square foot. HomeGuide notes that common 16-ounce sheet weighs about one pound per square foot. The code minimums apply here because Jackson enforces the 2018 IRC:
Sheet roofing
16-ounce cold-rolled copper, or 12-ounce high-yield copper (Table R905.10.3(1)).Preformed shingles
12-ounce copper.Fasteners
Copper, brass, bronze, copper alloy or 300-series stainless (R905.10.4). A galvanized nail in a copper roof is a mismatch.Underlayment
HomeGuide mentions a breathable felt under copper panels to keep trapped moisture from damaging them. Ask what goes under yours.
Copper Roofing Color Over the Years
New copper is bright. HomeGuide says a natural light bluish-green patina takes 10 to 20 years to arrive, that a chemical treatment can age copper in a day or two, and that a clear coat made for copper can hold the shine. Decide which one you want before the job starts, because a clear coat goes on new metal and a forced patina changes the color right away. Against red brick it comes down to taste, so pick one before the copper is ordered.
Copper Roofing Runoff and Mixed Metals
The Metal Construction Association says copper "has a very severe corrosive effect on steel, aluminum, and zinc", and that it works well only with lead or stainless steel. It also warns that water running off a copper roof onto a Galvalume surface causes corrosion and staining, even when the metals never touch. VMZINC lists copper among the metals zinc can't be in contact with.
That matters on a house where a copper bay sits above a steel porch roof or steel gutters:
Look at where the water goes
Water off copper shouldn't drain across a steel or aluminum roof below it. Ask how the roofer will route it.Keep the metals apart
Flashings, cleats and fasteners touching copper should be copper or stainless.Match the gutters
Copper gutters under a copper roof, or a plan for the transition. See gutters for metal roofs and Galvalume metal roof for the steel side.
Copper Roofing Cost and Bid Lines
HomeGuide's national range for a copper roof is $13 to $30 per square foot installed, and $27,000 to $80,000 for a whole standing seam copper roof. A single bay or entry roof costs far less, so ask the written bid to name:
Copper weight
16-ounce cold-rolled, or 12-ounce high-yield.System
Standing seam, flat-seam soldered or shingles.Fastener and cleat metal
Copper or stainless.Flashing into masonry
How the copper meets the brick wall or chimney.Finish
Natural weathering, forced patina or a clear coat.
For aluminum, the other non-rusting option, see aluminum roofing.