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Hi all. Have been told not to use lead flashings with rain water harvesting. If this is so, what alternative flashing materials are readily available.
PS thanks to all for the advice we have had from this forum so far without having to ask a single question until now.
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On what grounds did they say not to use lead for flashings? Are you intending to drink it or use it for grey and/or garden? Am looking at a harvesting system at the moment. Copper or zinc have both been used for roofing and flashing in the past.
Surely they don't recommend replacing all leadwork when fitting a rainwater harvesting system to a house with existing lead flashings? Un-patinated lead does form lead carbonate with rainwater, which is a very strong bleach. Maybe this is what they're concerned about or corrosion to pumps etc.
Apologies if this has all been kicked around the forum in the past.
Cheers,
OJ
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Best idea if you already have lead flashings is to treat them with patination oil or linseed oil. This will be a prety effective measure for stopping lead disolving in the rain water. It can't really do that anyway as it disolves best in old pipes left over long periods of time.
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Rain water contains nitrous and nitric acids (from lightning actually) that will disolve small amounts of lead. Sulphuric acid from acid rain will not dissolve lead as lead sulphate is insoluble (hence its use as a white pigment in paints of yore). All that said, the amounts of lead nitrate in any harvested water will be minute. If you use copper flashing, you will also get copper salts in solution (which are also toxic). Galvanized or zinc flashing will give you zinc salts in solution ... and zinc as a trace element is supposed to be essential for sperm production! Might want to look at galvanized flashing then!
Paul.
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I have recently heard that 'lead' flashing is no longer pure and that is alloyed with tin. Don't know if this affects the discussion or even if it is true. Anyone?
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Compared to the area of the roof, very little of your rain will touch the lead. I doubt whether it's a matter to get very exercised about.
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