Cleaning Copper Roofing Techniques

Copper roofing can be a beautiful touch to a building, whether the roof is clean and bright or possesses the characteristic green hue unique among roofing systems. However, copper roofs can also quickly become black and mucky looking. You can spiff up your dirty copper roofing by cleaning it with either of the following homemade techniques, avoiding the use of expensive commercial cleansers.

Homemade Cleaning Paste

It is possible to effectively clean your copper roof by making your own moderately acidic cleanser using common household items. You can create your own cleaning pastes out of either one of the following “recipes”:

Recipe 1: Equal parts vinegar (apple vinegar works best, but any white vinegar will do), flour and table salt
Recipe 2: Tomato Ketchup

Keep in mind that you will need to leave whatever cleaning paste you decide to use on your roof overnight. This has two implications: firstly, you’ll need to clean your roof on a night without rain; secondly, tomato ketchup, while effective, probably isn’t the best choice to slather on a roof overnight due to the smell.

Once you have your cleaning paste made, you’ll need to apply it to your roof. This can be done with whatever tool you want, even your fingers; the only important thing here is to apply it evenly across the entire surface of the roof. Leave the paste to break up the grime overnight, or for 8-hours minimum. When enough time has passed, rinse off the roof with warm, soapy water and again with fresh water. Use a clean towel to dry and polish the roof. Congratulations, your roof is beautifully clean! You can help keep it that way by applying a clear lacquer or polyurethane spray once it is completely dry.

Lemon Juice Scrub

If you need your copper roof clean in a single day and don't mind applying a little elbow grease, you can clean it with a lemon juice scrub. To make it, combine 3 parts lemon juice to 1 part coarse salt. Don’t use table salt, as it will dissolve and reduce the effectiveness of the scrub. Use a hard but nonmetallic scrubbing brush with a lot of force to scrub the lemon-salt grit into your roof. You don’t need to worry about scratching your roof as long as your scrubbing brush has bristles, not metal, so throw your full weight behind it. It’s best to start at the top of your roof and work your way down, as runoff which leaks onto the lower part of the roof will have a little time to penetrate the grime and make your job easier. Once you are done scrubbing your roof, rinse it with fresh water while being careful not to touch it with your hands. Finish the job with polyurethane spray or a clear lacquer if you’re so inclined.