Cleaning copper roofs

A. I have some experience with copper roofs. I assume someone has attempted to paint or (horrors!) tarred over your copper? Anything you use in a chemical line will require careful control of the runoff, and may leave the copper rather streaked or spotted unevenly. Good luck.

A. If a roof has not been painted I would suggest a stiff brush and a mildly acidic solution, there are a great number of things available that will work just fine provided you are willing to put in the elbow grease (ketchup is an unusual example, but it does work!) If you are looking for something that will not ruin the lawn or plants around the roof I suggest Kool-Aid or some other powdered drink mix, mix it with a bit of water, rub it on and scrub with a will, it's mildly acidic and non-toxic to the plants that you may have below the roof, the first rain will remove the sugary coating that is left when it dries (or just rinse with water). If you are intent on the copper staying bright I suggest looking for a clear spray on lacquer (test it somewhere it won't be seen first).

A. Bob,

I'm willing to bet that those rust streaks are caused by the nails holding your roof in place. Copper and alloys with a high quantity of copper in their mix usually oxidize into either a brown or green color.
I would suggest looking at the nails that were used on your roof, if they were steel I would suggest you leave it be. If they are something else (like copper), pressure wash the roof with a mild citric acid (5%) solution.

A. Clean copper with Ruby Fluid =>
you can buy it at heating and cooling supply warehouses. After cleaning with Ruby Fluid, wash with soap and water. To keep shiny forever use a clear brush on brick seal made by Geocel =>

brett smith
- quitman arkansas usa

A. Hi!
I discovered, after using various cleaners, that sanding my copper cupola with 150c sandpaper in a single direction brings out the beautiful copper color the best! Ketchup got the big stains off, the sandpapering on one direction made it look like a shiny new penny! I was amazed after trying all these cleaners including ones mentioned here. The seams, the edges all come out beautiful using different grade sandpaper, from fine to heavy grit. Simply clean up with fine 150c or finer, push in one direction so the copper doesn't show circles or scratches at all. Next, I'm going to polyurethane it to seal it and mount it back on the roof! GOOD LUCK ! /Pete

A. Hi Raymond. If you've tried multiple products that were specially formulated for the particular purpose and found that they still weren't effective enough, you probably should change tack because there is no magic chemical that you as a consumer will find that the specialists who have researched it for years were unable to find.

But if you are willing to try a two-step process instead of a one-step one, you could try vinegar plus salt, which is a very aggressive copper cleaner. It will leave the copper a "salmon color" rather than the color of a new penny, but you can then try any commercial copper polish to see how quickly and easily the "new penny" color comes back.

You may also be interested in letter 29955, "How to brighten and restore copper dome on historical building". Best of luck.

A. Hi Tiffany. If it's green and has stained the stucco green, then there is copper in it, although I suppose it's possible that it might be copper plated steel rather than solid copper. You can attach the picture in email to mooney@finishing.com.

Regards,

A. I just finished a day at trying to clean my copper roof over a bay window. Started with vinegar/salt/flour and that worked a little bit - say a few speckles of copper showing through after several hours of brushing/rinsing and repeat. Graduated to Comet and a Scotch Brite sponge and not much better. Got really brave and got out the steel wool and rubber gloves and gave it some elbow grease. A few more specks, but no where near shiny copper. Next reached for the palm sander and fine sandpaper - wholly smokes did that do the trick. Sanded for a few hour and got into the corners with a wire brush wheel on my drill. Cleaned it all off with mineral spirits and just gave it a coat of Minwax lacquer - looks like a brand new roof! I know the palm sander left a few circular sanding marks, but the roof is 7 foot from the ground, so unless I invite Shaq over for a BBQ, I don't have any worries.