Copper Oxidation Stains

[Harold Brantley]

I washed a lot of concrete steps today that had green stains coming from the copper flashing on the roof ridge and around the dormers. Pressure alone only removed about 50% of the stain. Do any of you routinely run into this problem and have you found a chemical that removes this green copper stain?

 

[Glenn]

Harold,
I would try H F acid (aluminum brightener). If not available try oxalic acid.
Glenn

 

[hadishon]

I have a potential client that has a lot of copper staining on their concrete from a copper awning. Has anyone found anything that worked well?

If I get the job, I'm thinking of trying oxalic acid or CLR.

Anyone found something better?

 

[chirobob]

brick cleaning code

Harold,
try downloading the brickcleaning code from this website www.claybrick.com.au in pdf format. It has solutions to many stains, as well as a good reference to show the client to give you credability and a possible underlying reason for the stain (reaction etc.) . I always show them when it was published as well, so they know it is up to date. I have found that most of the remedies you need to increase the strength by double or more.
Cheers
Jason

 

[Tim Lynch]

Originally posted by Glenn
Harold,
I would try H F acid (aluminum brightener). If not available try oxalic acid.
Glenn

oxalic acid will age the copper thus more green. Did a deck with railings that were copper just last week, oxalic acid turns them white and then the green starts, My customer wanted this look before I started the job,

Regular copper hey I thought that oxyclean brightens copper? Maybe Im wrong but I thought I saw that on a commecial.

 

[Mikespowrwash]

As far as removing the green stain left behind on brick, I just cleaned a brick patio that is under a copper roof that has no gutter. The stain was right where the rain runs off the roof and the whole length of the patio. I used an acidic solution and cleaned the whole patio to make sure all the joints looked uniform in color. I mixed it at about 20% strength and applied with bucket and brush with 2 applications keeping it wet the whole time then just rinsed it all away. It came out and looks great but im sure it will be back soon due to all the rain and no gutters up on the roof. I explained this to the homeowner and she is aware of this problem but doesnt want any gutters up there. Looks like job security, I may try a sealer next time around to see if that will help. I used Sure Klean but thats because I had some in the truck Im sure a light dose of HF or muriatic would do the trick as well. Always test first in a small area to make sure the result you want can be achieved.