Once a Planning Permission has been granted it is then worth proceeding to Stage 2 (although you can do this at the same time as Stage 1 to save time, particularly if you think Planning Permission is likely).
The Building Regulations are a set of minimum government standards relating to aspects such as structural stability, hygiene, insulation, etc. There will be a Building Regulations fee, payable separately to the Council, in due course, assuming this stage is reached. The amount will depend on the size/cost of the proposals and will be payable in 2 stages, the first when plans are submitted and the second after the first of a series of site visits if and when building work starts.
Input from our Structural Engineer may be required as part of Stage 2 including structural calculations for any steelwork, advice about foundations, etc. Paul Ennis & Company Limited include all structural design as part of our brief.
Input from our Thermal Engineer will be required as part of Stage 2 including thermal design (U Value) calculations for any heat loss compensation and specific glazing and thermal design. Paul Ennis & Company Limited include all thermal design as part of our brief.
Although construction prices vary considerably and much depends on the specification, £1,250.00+VAT per square metre of total new floor area should give you a reasonable guide for typical domestic work (excluding the cost of other alterations and VAT).