Replacement barn - Detailed structural drawings

We require detailed drawings and structural design for a replacement barn and stables. Schematic drawings are attached but require detailing for construction and all structural design drawings completing. There are 2 elements to the building. The taller building is approximately 16.5m x 9m and 5.6m tall, the lower building is 23.5m x 6m (plus 1m overhang) and 3m tall. This building will initially be open fronted. We would like the roof of the main building to appear as flat as possible. We will use Kingspan insulated roofing sheets (KS 1000 RW) or similar. This system allows pitches as low as 4 degrees. The roof to the main building will be hipped and hidden behind a parapet. The buildings will initially be used as general farm buildings but with scope for conversion. I have attached a second set of schematic drawings showing the possible conversion in years to come. We require the design to enable the easy conversion to residential in years to come. The pink beams are all stage 2 and the red posts would be removable for stage 2. These drawings are schematic only and require detailing. Note: the sketches provided are schematic. The design can change if necessary as required and can incorporate a steel frame or a combination of traditional masonry with steel beams. The drawings, specification and calculations should be to building control standard.