Structural calculations are designed by the engineer based on alterations being carried out on the new preferred layout the home owner requires to their property. The engineer provides a steel design which includes fabrication detailed drawings to present to the builder and how the beams and columns are connected together.
The structural calculations are the workings of the engineering design based on strength, size, fixing and elements of the new structure put in place. Calculations include windloads, deadloads and liveloads in maths format.
The calculations are needed to back up the engineer's analysis design based on his workings. The building control inspector requires these structural calculations to read the formulas of the engineer's workings to establish if his works have been designed in accordance.
Once the building control inspector has approved the engineer's works, i.e. the fabrication drawings and calculations, the builder will then order the steel beams based on the engineer's structural design. So for all #loftconversions and #extensions that involve any additional structural elements, they need to be designed by the engineer which will produce fabrication detailing #drawings and #calculations to back up the design.