We have a stand alone office in our warehouse. I need to calculate load bearing capacity (PSF)of the roof. The roof is constructed of 2x6 joists on 24" c/c, 11'6" span, 9'4" wide, with a 3/4" plywood sheeting on top. We also have a forklift manlift basket 48" x 48" x 50" high, constructed of...