Lead coated copper mixing with alumin...

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Author Message David Sisson Member Username: david_sisson Post Number: 3 Registered: 06-2010 Posted on Wednesday, October 11, 2017 - 03:50 pm:    Hi, I'm working on a reroofing project of an elementary school. Of course, almost all of the metal waterproofing details are lead coated copper, which has performed fine, but is so beat up that the school feels it's failed. We want to replace it. Coastal environment. Coated aluminum details - high on the roof - have performed very well and look great. Lead coated copper - low on the roof - looks horrid. I'd like to replace the LCC with coil coated aluminum but can't get rid of all of the LCC - since some is through wall flashing. I'm concerned about runoff - from the tiny bit of LCC onto the coil coated aluminum. I'm wondering if this will corrode the aluminum. We would not mix aluminum directly to LCC, but might replace some LCC step flashing with plain copper, so I potentially could have copper touching LCC, and both running off onto coil coated aluminum. Am I going to have a galvanic issue / corrosion? If yes, I'll probably switch everything possible to plain copper. Any suggestions are much appreciated ken hercenberg Senior Member Username: khercenberg Post Number: 1115 Registered: 12-2006 Posted on Thursday, October 12, 2017 - 10:46 am:    I would talk with Larry Peters at CDA: Larry Peters Project Manager, Building Construction Copper Development Association Inc. P.O. Box 1206 Decatur, GA 30031 www.copper.org office: 404.373.0324 E-mail Address: Larry.Peters@copperalliance.us David Sisson Intermediate Member Username: david_sisson Post Number: 4 Registered: 06-2010 Posted on Tuesday, October 17, 2017 - 05:02 pm:    Thank you Ken, I'll reach out to him. David Sisson Advanced Member Username: david_sisson Post Number: 5 Registered: 06-2010 Posted on Tuesday, October 24, 2017 - 02:57 pm:    To follow up: 1) I discussed with Larry Peters. He couldn't really talk to the topic of lead vs aluminum (after all, he represents copper), but he did feel that trace lead coming off onto copper would be OK. 2) I spoke with a large coil coating and aluminum building products manufacturer. They suggested touching up aluminum cut edges with an automotive paint to match the coil coat. I'm probably also going to spec painting of the exposed LCC, to reduce the amount of lead coming off.