Standing Seam Flat Copper Roofs – Pros and Cons

Copper is a pretty good material for roofing. Copper, in sheet metal form, is both durable, lasting in many cases over 50 years, and it can be very lightweight. This makes copper a terrific building material for certain types of waterproofing and flashing. Copper roofing can also be a beautiful accent detail used on small roof buildings where those roofs are visible from the ground. Examples may include portico roofs, cupulas or even small porch roofs.

However, copper isn’t perfect and has a few downsides. Firstly, copper is extremely expensive. One of the biggest selling points for copper is that it is a historically beautiful building material, but on a flat roof, in many cases you’ll never get a chance to see it from the street or facade view of a building. Especially in installations on a flat roof. Generally, flat roofs are above the angle of a typical view. In cases like this, copper is still extremely expensive but you don’t get the aesthetic architectural benefit from copper roofs.

Another downside or problem inherent in copper roofs is that copper sheet metal expands significantly in conditions of thermal change or temperature fluctuation. This significant fluctuation factor, becomes a problem where individual pieces of copper are joined together or where individual elements of copper sheet metal have materials that penetrate through the roof system. Typical flat roofs, for example, often have many distinct penetrations through the roof.

Types of elements that penetrate through flat roofs for functional purposes include the following elements:

  • Skylights
  • Total package AC and furnace combo units
  • Air ducts
  • Plumbing vent pipes
  • Exhaust air vents
  • Power supplies or feeders
  • Refrigerator lines
  • Mechanical control wiring
  • Photovoltaic mounting elements
  • Photovoltaic electrical wiring
  • Chimneys

The picture below shows an example of a standing seam copper roof in Washington DC.


In the slightly closer view shown in the photo below, you can see there are several additional elements incorporated in the overall roof system.   This particular rooftop has a vent pipe near the center of the roof. The vent pipe stands high above the rooftop and terminates with a gooseneck. Goosenecks are not required by code for plumbing drain vents because rainwater entering into the drain system is permitted by the building code.

This particular rooftop also includes a roof access hatch. The access hatch cover is clad with copper as well, similar to the adjacent field of the low slope or flat roof.

There are 2 skylights on this roof. Both happened to be acrylic dome style skylights but the larger skylight shown at the right is an opaque acrylic, while the one to the left is clear and entirely transparent.  In one of our next blog article we will talk much more about details, options, features,  and characteristics of skylights.


Standing seam sheet metal roots of this type are composed of individual strips, generally 16″ in width with a 2″ high standing seam. The standing seam of one panel of metal abuts against the standing seam of an adjacent panel of roofing metal. Those two individual sections are then rolled together. Longitudinally, in the case of the roof below, from front to back, where the roll source material is joined with another piece of material, the upper portion of material is laid after the lower portion and therein has an overlapped or overlaid seam which allows rainfall in low wind conditions to flow uninterrupted or undeterred without entering the building.

Smart proactive replacement, construction, upkeep and maintenance of low slope roof systems requires an enthusiastic interest and understanding of waterproofing principles and building science.   Here in Washington DC, historic and modern residential and commercial buildings are extremely expensive and the roof and related systems provide the shield that preserves the building.

We encourage all of our clients, and all readers of this article and to our blog in general, to prioritize the value of quality construction and building maintenance, and develop a relationship with our company.  You can learn a lot more on our blog.  Feel free to check it out.  If you have questions about the roof and related systems of your building in Washington DC, fill out the webform below and drop us a line.  We will be in touch if we can help.



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