Tips from the Architect: Copper in Architecture

October 26, 2016

The use of copper in architecture dates all the way back to the 3rd century BC, with two notable examples being the roof covering of the Pantheon and the roof of the Danish castle Kronborg (made famous by Shakespeare as the setting of Hamlet’s castle Elsinore). Both as a building material and as a striking design choice, it has stood the test of time. Copper is a great choice for homeowners seeking a material that is both unique and durable.

The Benefits of Copper

  • The surface of copper develops a patina over time, which protects the copper below and resists corrosion.
  • It is very durable and can last hundreds of years – great for sustainability.
  • It is recyclable, and the quality holds up.
  • Copper is a low maintenance material that requires no cleaning.
  • It has a low thermal expansion compared to other metals.
  • It is lightweight. A copper roof is ¼ the weight of a tiled roof – this also means a lower cost for roof support.
  • In residential applications, copper and its alloys are frequently used for lightning protection. The most common alloys of copper are bronze (copper and tin) and brass (copper and zinc).
  • A copper roof can tie in stylistically with other copper elements like downspouts, scuppers, and flashings.
  • Copper can have a higher initial cost than other roofing materials, but its longevity and low level of maintenance make up for this over the long term.

A History of Copper in the United States

The origin of rolled copper in the US is rooted in Boston’s history. Benjamin Stoddert, Secretary of the Navy from 1798-1801, wanted a strong navy but also hoped to decrease dependence on Britain for copper products. Copper creates an oxide coating when it interacts with seawater, making it an ideal material for the bottom of a wooden ship, as it protects the wood and prevents build-up of barnacles and residue. Stoddert reached out to Paul Revere to encourage him to develop a process for cold rolling copper here in America.

In 1800, Paul Revere received a loan from the Federal Government, purchased a mill in Canton, MA, and converted it into a copper rolling mill. Revere had been rolling silver since 1785, but it took him a few years to master the process. In addition to “coppering” the navy fleet, in 1802 Revere also covered the dome of the new Massachusetts State House with his copper sheets. He was the first American to roll sheets of copper as a successful business.

Thanks to the process laid out by Revere and perfected over the years, rolled copper is now an accessible element for residential applications. Today it commonly comes as lead coated copper. The lead helps the roof from weathering and is easy to manipulate as it is malleable. Lead coated copper does not stain brick, stone, or other porous materials, can be painted or allowed to patina, and is very watertight when installed properly. From a design standpoint, lead coated copper is sometimes selected for those seeking gray color tones as opposed to the red coloring of copper. This allows for more flexibility, as homeowners can decide how bold they wish to be in using copper as a design accent.

Whatever your design preference, copper can lend durability and character to your home that will last for years to come.