Copper is one of the most beautiful roofing materials available—its warm red tones gradually age into an elegant green patina over time, which gives a building character. In addition, a properly installed copper roof can last well over 100 years without much maintenance. However, when a copper roof does need to be repaired, it helps to know more about the two major issues that you need to consider before tackling the job
You may have to replace sections of copper, rather than repair them.
One of the reasons that copper is so useful for roofing is that it can be beaten into very light, thin sheets. That makes it easy for the underlying structure of the building to hold up the weight of the copper roof. Unfortunately, that thinness can also lead to long-term problems when the copper can't withstand the environmental conditions in the area after a while or is improperly installed. It may make it impossible to repair sections of the roof without actually replacing some of the copper.
For example, fractures and cracks are common along the joints where the copper sheets meet because of the stress the metal undergoes with extreme temperature changes. Fractures can also result from damage to the metal during an improper installation process. Heavy hail or wind-tossed debris can actually punch holes in copper roofing that's too thin.
Unfortunately, repairing any of these problems can be difficult to do without simply removing the damaged copper and replacing it. It could be impossible to seal cracks, fractures, or holes in the existing copper with glue or tape in a way that adequately protects the underlying structure from leaks and other damage.
You may have to artificially add a patina in order to preserve your roof's aesthetics.
The copper may also experience corrosion due to acidic chemicals in the area's rainwater and bird droppings. Both can cause the copper to become stained, destroying the beauty of the roof's patina. The only way to remove the stain is to strip the copper of its current patina. That's going to leave spots of your roof that aren't the same color as the rest.
Even though the patina on copper develops quickly, the exact shade is something that develops over time and is very dependent on the local climate and air quality. That means that if the climate or air quality in your area has changed in the decades since the roof was installed, new sections of copper or sections that have had the patina removed to clean them of staining may never obtain the same color as the rest of the roof. In order to combat this, there are chemicals that can be applied to the affected sections of copper to bring it as close as possible to the color on the rest of the roof.
For more information on metal roof repair, talk to a professional roofer in your area.