Hi, hope someone out there can help. Want to build a flat roofed gazebo. The size is 4.5m x 4.5m. I know that I need joists of 220 x 47 [9x2] to span at 400mm centres. But I want to connect these at each end to wooden joist spanning two pillars. What I cant seem to find is what size should the wooden joists be to hold what will be 10 internal joists.
