Copper Roof Turning Green Chemical Change

Copper can also turn gray brown or blue in some circumstances.

Copper roof turning green chemical change.

The patina actually protects the copper below the surface from further corrosion making it a good water proofing material for roofs which is why the roofs of so many old buildings are bright green. As the years pass and the roof ages the patina will thicken and change colors. This change occurs as a result of a chemical reaction between the copper moisture and oxygen referred to as oxidation. The exterior of the statue of liberty is made of copper about the thickness of two.

The gradual slide from appearing as a newly minted penny through its brown black and green phases is an oxide sulfate patina or coating that s. This is a chemical change because copper oxide is a substance that was not there before. Eventually the roof will even out to a brilliant green. Why copper roofs change color unlike iron that rusts and deteriorates as it ages under wet and airy conditions copper undergoes a chemical change where it actually coats itself with a preservative.

The only way to prevent a copper roof from turning green is to prevent this reaction from occurring. First copper doesn t turn green it reacts with oxygen in the air to form copper oxide. This layer known as a patina is incredibly thin.