It is not so much the “common” items that add costs for joist and joist girders, as it is the “uncommon” items. These can be using frame connections for support beams when drop in headers or beams will do, requiring shop installed webs for concentrated loads instead of having them field installed, using odd depth joists or joist girders, i.e., 33LH or 47G), transferring high axial loads through joist bearing seats instead of using tie plates, rods, or angles, using slip critical connections for joist or joist girders connections. Requesting joist calculations for a project should incur additional costs.