Where copper goes on a house
| Feature | Usual copper system | Why copper here |
|---|---|---|
| Bay window roof | Standing seam or flat-seam panels, shaped to the bay | A small, highly visible roof where copper's look pays off |
| Front entry or porch roof | Standing seam on steeper roofs, soldered flat seam on low ones | Frames the front door and ages with the house |
| Dormer roofs and cheeks | Standing seam or flat seam | Ties dormers into a slate, tile or shingle main roof |
| Chimney cap and shroud | Fabricated copper cap | Doesn't rust, and pairs with copper flashings |
| Valleys, step and counterflashing | Copper sheet flashing | Lasts as long as slate and clay tile, so the flashing doesn't fail first |
| Gutters and downspouts | Half-round or box copper gutters | Finishes a slate, tile or copper-accented home; see gutters |
| Full roof or large section | Standing seam copper | Landmark and estate homes, cupolas, turrets, towers |
How copper is specified
- Weight, not gauge. Copper roofing sheet is specified in ounces per square foot. 16-ounce cold-rolled copper is the usual choice for roofing and flashing; 20-ounce is used where more stiffness is wanted, such as wider pans or exposed spots. ASTM B370 is the standard for copper sheet in building construction.
- Seam type follows the slope. Standing seam (single or double lock) on steeper roofs; flat-seam panels, soldered watertight, on low-slope bays and porch roofs; batten seam where a traditional look is wanted.
- Fasteners and cleats in copper or stainless. Never steel or galvanized, which corrode against copper.
- Room to move. Copper expands and contracts with heat. Cleats hold the pans while letting them slide, and long runs need expansion details.
- High-temperature underlayment under copper, with a slip sheet where the manufacturer or handbook calls for one, so the metal doesn't stick to the underlayment in summer heat.
The Copper Development Association publishes the detailed reference most copper work follows, its Copper in Architecture design handbook. We follow it and the job's drawings.
Patina: what your copper will look like
New copper is bright penny-colored. Within months it darkens to russet, then to brown over the next few years. The blue-green verdigris takes much longer, and in a relatively dry climate like North Texas it can take decades and may stay patchy, especially on sheltered surfaces like bay roofs under an overhang. Copper needs no paint or coating; the patina is the finish. If you want the green look now, pre-patinated copper exists, and if you want to hold the bright color, that takes clear coatings and upkeep.
Copper and other metals: the galvanic rule
When copper touches steel, galvanized metal or aluminum in the presence of water, the other metal corrodes. Runoff from copper does the same thing downslope. So a copper bay roof should drain into copper gutters (or be separated from aluminum ones), copper flashings get copper or stainless nails, and copper never sits directly on steel. Water off copper can also stain light stone, stucco and concrete with green streaks over time, which we plan for at drip edges.
Copper and hail
Copper is a soft metal, and hail can dent it. Heavier 20-ounce sheet resists denting better than 16-ounce, and sheltered features like bay roofs under an eave see less impact. Dents usually don't make copper leak, but they show. Homeowners who want the copper look on a large, exposed roof sometimes choose a copper-tone painted steel standing seam instead. We form standing seam and R-panel/PBR in 24 or 26 gauge steel on our own roll formers, cut to the measured length of each run. Metal lead time is typically 1 to 2 weeks. Painted steel won't develop a patina, and color warranties come from the paint maker.
Copper with slate and tile
Slate and clay tile can last for generations, and copper is the traditional flashing for them because it lasts nearly as long. Cheaper flashing that fails in 20 years means pulling up sound slate or tile to replace it. When we repair or reset slate or tile, we replace worn valleys and flashings in copper where the roof calls for it.
HOA and historic approvals
A copper accent is a change of material, so many HOAs want it reviewed. We prepare the submittal with drawings, the copper weight and system, and photos of the patina stages. On a designated historic home, a change of roof material can need city historic review. Our HOA roofing page covers how we handle approvals start to finish.
What drives the cost of copper work
We don't publish copper prices, because copper work is priced from the drawings and the copper market. The main factors: copper weight (16 or 20 oz), the size and shape of the feature (a curved bay or turret takes far more fabrication than a flat porch roof), seam type (soldered flat seam is labor-intensive), how much flashing and gutter work is included, access and staging, and the current price of copper sheet. See what drives the cost of a high-end roof for the full list.
Questions to ask any copper bidder
- What copper weight, and is it cold-rolled roofing sheet?
- Which seam type, and are low-slope areas soldered?
- What are the cleats and fasteners made of?
- What underlayment and slip sheet go under it?
- Where does the water go, and does it touch any steel, galvanized or aluminum?
- Can you show copper work you've done yourself?
Every inspection comes with a free digital photo report, so you see what we see. We're certified with GAF, CertainTeed, Owens Corning, Atlas, Johns Manville, Carlisle, Tropical Roofing Products, Mule-Hide and Enviroshake, and many other roof manufacturers.
Residential warranty: a workmanship warranty from 10 years up to lifetime, depending on the job, with manufacturer warranties up to lifetime. Manufacturer coverage depends on the product and brand, and on the project qualifying for that manufacturer's program. We put the exact warranty for your roof in writing.
Certified, with 30 years installing every major roofing brand, a family roofing business going back 75 years, and over $80 million in completed roofing projects. 5.0 stars on Google at all three of our offices.
Request a free inspection or call (817) 733-9228. Small repairs are welcome too.
