Roof joists are horizontal structural customers that help the roof deck and framework, transferring the load to the partitions beneath. Right joist sizing and spacing make certain structural integrity. Putting in metal roofing requires nailing sheets with overlapping seams to purlin strapping that operates perpendicular on the rafters. Roof vents: https://www.prettypracticalhome.com/finding-the-best-roofing-contractors-in-illinois-your-ultimate-guide/