Its a mono pitch type roof (like a lean to type) so the overlaps would
be on the width of the roof. One sheet (length) will cover the slope of
the roof in one go so the only joins will be on the width of the sheets.
Its an small extension for my shed to create a `dry` area to work in
when there is light rain. It wont have any sides to it, just the roof, a
bit like a carport.