While one of the objectives of this design is to keep the framework as modular as possible to facilitate take-down and moving the mews, the roof covering will present some special problems as the decking needs to be securely fastened to the joists and the covering will be a seamless sheet of white EPDM rubber roofing. I'm still working on this size problem.
The joists were limited to 2x4s glued and screwed together to form laminated beams of a sort so that the interior head room could be maximized. I'm 6'-3" tall and do not want to have to bend over every time that I'm in the mews. The entire height of the mews is limited to 8' by our Housing Association. The pergola design was based on HA requirements and the desire to have the mews look like a backyard accessory and not an eyesore.