Lead Flashing

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Author Message Gerard Sanchis Senior Member Username: gerard_sanchis Post Number: 86 Registered: 10-2009 Posted on Wednesday, February 13, 2013 - 08:01 pm:    Can lead, as in flashing, be soldered to stainless steel? ken hercenberg Senior Member Username: khercenberg Post Number: 431 Registered: 12-2006 Posted on Wednesday, February 13, 2013 - 08:32 pm:    I know that you can use lead-tin solder when soldering stainless steel but it essentially fails so quickly that no one would ever suggest it. There used to be decorative lead-coated stainless steel but it was replaced, primarily by terne-coated products by Follansbee. I have no idea if anyone else makes this now or if Revere will be producing it now that they've bought out Follansbee. After all, Revere is all about copper. I presume that corrosion would be a major concern. I also presume that appearance is not important for your application; lead solder turns ugly before it dissolves. I'd have to presume the same would be true when soldering lead sheet to stainless. spiper (Unregistered Guest) Unregistered guest Posted on Thursday, February 14, 2013 - 09:40 am:    In general stainless steel and lead are not that far apart in the galvanic reaction chain but it would be important to know the type of stainless you have and I believe an acid flux solder could cause accelarated corrsion problems. Any reason why you can not simply use the same material rather than mixing metals? (formability?) Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 1300 Registered: 07-2002 Posted on Thursday, February 14, 2013 - 12:30 pm:    you have clients who will still let you use lead? Richard L Matteo, AIA, CSI, CCS Senior Member Username: rlmat Post Number: 563 Registered: 10-2003 Posted on Thursday, February 14, 2013 - 12:46 pm:    The use of lead flashing has been banned in public school projects in California. I pretty much stopped using it for all other projects as well. Gerard Sanchis Senior Member Username: gerard_sanchis Post Number: 87 Registered: 10-2009 Posted on Thursday, February 14, 2013 - 02:53 pm:    Thanks to all. The project calls for all exposed flashings to be lead. It is not a school but someone’s idea of what a roman civic building looked like – actually Pompeii still has lead flashings visible in place, if memory serves me well. California is, I believe, only one of 2 states that still allow lead where water runoff can contaminate the phreatic table. Europe still uses lead on most buildings, even residential work, for flashings and on some building for roofing - an example is Notre Dame Cathedral in Paris which has a lead roof approximately 30 mm thick. European buildings are expected to have a 100-year life and lead probably has the longest life of all commonly used flashing materials. The issue was resolved when we decided to make all flashings out of lead and got rid of the stainless steel. ken hercenberg Senior Member Username: khercenberg Post Number: 432 Registered: 12-2006 Posted on Thursday, February 14, 2013 - 03:34 pm:    Good choice presuming you can find people who know how to handle lead. It's soft and the sheet can tear and split if not handled right. Still, it is beautiful. There are some incredible soldered lead roofs and domes where the lead sheet is shaped into various patterns. The solder joints highlight the pattern. True artwork. I loved working on the roof repairs at Basilica of the National Shrine of the Immaculate Conception in Washington, DC. Any chance to get some of that on your project? The detailing is incredible. Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 1301 Registered: 07-2002 Posted on Thursday, February 14, 2013 - 05:10 pm:    The Northwest didn't have a ban on lead, but there was so much public outcry that no architect would even dream of using lead for any institutional (school, health care, public building) project anywhere. There would probably be "concerned citizens" picketing the office. I've always liked it -- and thought that lead was a better material than many, especially for flashings. ken hercenberg Senior Member Username: khercenberg Post Number: 433 Registered: 12-2006 Posted on Thursday, February 14, 2013 - 05:45 pm:    I suppose there is a possibility that lead can leach into the groundwater after running off a roof or flashing surface. Can't be too careful, we might end up becoming French. Talking about lead in our water supply, I'm amazed at the requirements in the new (2010) Drinking Water Act http://www.law.cornell.edu/uscode/text/42/chapter-6A/subchapter-XII Apparently the belief is that lead can leach out of brass alloys and pollute drinking water. We're not talking about lead solder on copper pipes. We're talking lead content fully captured within a brass alloy. Apparently the organic compounds, and the chemicals added to kill those compounds, can result in a cocktail that causes lead to leach out of the brass. Seems to me that the bacteria, chemicals, etc. are at least as scary as the lead. Anon (Unregistered Guest) Unregistered guest Posted on Friday, February 15, 2013 - 10:47 am:    Where has common sense gone? Lead flashing is a very good material for vent stacks on the roof - typically 15 - 20 feet above ground level. Who knows or can definitely say what miniscule amount of lead might leach out and find its way into ground water? And, how many adults / children have you seen on a roof eating lead flashing? ken hercenberg Senior Member Username: khercenberg Post Number: 434 Registered: 12-2006 Posted on Friday, February 15, 2013 - 11:02 am:    This is America. Common sense has nothing to do with public health policy. Lynn Javoroski FCSI CCS LEED® AP SCIP Affiliate Senior Member Username: lynn_javoroski Post Number: 1609 Registered: 07-2002 Posted on Friday, February 15, 2013 - 11:07 am:    And common sense is extremely uncommon anyway Lisa Goodwin Robbins, RA, CCS, LEED ap Senior Member Username: lgoodrob Post Number: 210 Registered: 08-2004 Posted on Friday, February 15, 2013 - 11:59 am:    As far as I know, in the Northeast there is no ban on using lead roofing, even in the middle of a watershed area. From my research, the only times I will add lead to a specification, without raising a huge fuss, are for historic restorations and radiation control. - John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1477 Registered: 03-2002 Posted on Friday, February 15, 2013 - 02:43 pm:    Gerard, I'm wondering if you meant 3 mm thickness for the roof of Notre Dame rather than 30, which is about 1-1/4 inches thick. Also, it seems to me that soldering together dissimilar metals would be a mistake due to differential movement. How about a sealant-filled crimped seam? Ken, we have specified soldered stainless steel for years and never had any pushback or reports of problems. Has anyone else experienced this as an issue? ken hercenberg Senior Member Username: khercenberg Post Number: 435 Registered: 12-2006 Posted on Friday, February 15, 2013 - 03:06 pm:    I've used soldered stainless steel on many roofs and other applications. The solder is a lead-free, silver based (SN96) solder. Standard tin or tin-lead solder is usually not a good idea. From Kester - During soldering, acid fluxes deposit zinc chloride in the solder and this salt can not be removed. Exposure of the chloride to carbon dioxide and moisture initiates a corrosion cycle. The chloride reacts with the lead in the solder, converting it to lead carbonate. After the lead carbonate is formed, the chloride is free to attack more lead. The corrosion continues until the solder joint dissolves. Stainless steel makes for a beautiful roof. If the owner is willing to pay for it, and expects 100 year lifespan, silver solder (again, SN96, not SN60) is the way to go. BTW, my understanding is that the restrictions on using lead involves workers handling it. I don't know if OSHA actually has restrictions, but that is what I recall as being the justification for avoiding lead. Gerard Sanchis Senior Member Username: gerard_sanchis Post Number: 88 Registered: 10-2009 Posted on Friday, February 15, 2013 - 07:28 pm:    John, it is 30 mm, not 3 mm thick. If you ever have the chance to go on the roof of the cathedral when it's open to the public, you'll be able not only to see the roof but also the wood structure that supports it - it's quite impressive as you can imagine.