Christian McArdle wrote:

The advantage of the lead is that it prevents water entering the building

A quite desirable property, thanks to all who replied. I seem to be able
to get lead from sheds in 3m lengths, where my longest run will be
double that, anywhere sell longer? (then I might need a forklift to get
it up to the roof though)

If I stick with the 3m lengths, is an straight overlapped joint ok, or
better to aim for a wrap around like so?

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