The lathing is usually made of fresh timber 35 to 40 mm thick, which is sufficient for sheet metal roofing. You do not have to saw such lath, but you can cut the lath with a cutter. It is very easy to do and can be fixed to the roof using hooks. The main advantage is that no sawdust falls on the vapour barrier on the roof, or any oil drips on the vapour barrier, as happens with a chainsaw.
