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- can be divided into five main types -
- Drip, formed where lead
is lapped over a step in the substrate.
- Hollow roll, is formed when two sheets meet to form a standing seam which is
turned into a roll. (Illustration 1),
- Lap, where one sheet is simply lapped over the other.
- Welt, formed by turning the undercloak up by approx one inch, and the overcloak
by two inches, which is then folded over and lightly pressed flat.
- Wood roll, formed by dressing the edges of adjoining sheets over a wood core (Illustration).