One of the most common issues we see is that clients submit planning stage drawings rather than construction stage drawings, this means that we are unable to approve those drawings as they contain insufficent information. It is also far more difficult for your contractor to be able to correctly price the project if there is a lack of detail on what the project includes.
Whats the difference between planning and construction stage plans?
Planning drawings are a set of simplified drawings that allow the local planning department to establish the scope of the works and typically only give basic details of the size, aspect and apperance of the building.
Building Regulation Drawings however are a set of detailed drawings and construction details and go into much more detail than the planning application drawings. They set out the construction methods used and detail how the building is to be constructed (wall build ups, floor constructions, roof thicknesses, insulation depths) etc. In addition you will often need to submit supporting documents such as structural calculations from the engineer, heat loss calculations, and usually a detailed construction specification to enable us to approve them.
Check out this handy guide that explains more.