How much will it cost?

The cost of an extension or conversion

The initial consultation to discuss your options lasts an hour and is completely free of charge.

Our fees are linked to our 3 step process:

Step 1 (Design & Feasibility Report) starting from £750
As cost is often a deciding factor, you’ll want to know early on whether your project is “doable”. Step 1 of our process results in a rough drawing and estimate for the complete build (our fees + council fees + contractor’s fees). The design we produce at this stage will allow your contractor to give you a ballpark figure of his own.

Steps 2 (Planning Approval) starting from £620
The cost of Steps 2 varies depending on whether your job counts as Permitted Development or requires Full Planning Permission. We always quote our fees in advance of any work being carried out. Our fees are based on the detailed drawings and applications needed to secure council approval.

Steps 3 (Construction Drawings and Building Regulations) starting from £900
The cost of Steps 3 is based upon the level of construction detail required, to comply with building regulations. This will include construction details of the floor, walls and roof, internal elements and any beams that are required. Your contractor will need detailed drawings in order to provide you with a firm quote and for under taking the building work.

Spitfire fees

When meeting a client for the first time, the question we’re invariably asked is, “How much will it cost?” As no two projects are ever the same, costs vary. A lot depends on the size and complexity of your job. That said, we’ll know from the initial onsite meeting whether consultants and planning permission apply to you.

Consultant fees

Depending on your chosen design, you may need to employ the services of external consultants:

Structural Engineer, starting from £350 – for the design of beams, lintels, foundations and roof.
S.A.P Thermal Calculation, starting from £180 – for a design that includes large glazed elements.
Party Wall Agreement, starting from £250 – if your project affects a neighbouring building or structure.

We book the consultants for you and manage their involvement but ask that you pay them directly. All have been carefully selected for their expertise and competitive rates.

Council fees

Council fees depend on your design and need to be paid directly to your local authority:

Planning, starting from £172 – to approve the siting and general appearance of your design
Building Control ‘Plan Inspection’ Fee, starting from £225 – to approve the detailed design.
Building Control ‘Site Inspection’ Fee, starting from £409.20 – to approve the build onsite once complete.

These are all the costs involved in getting you to the point where your builder can start work. However, for clients who want absolute peace of mind, we can provide additional services such as detailed costings, a building condition survey, builder tendering and selection, production of formal contracts and contract management.

Our aim is to offer simplicity and transparency – services that are easy to understand and quotes that don’t include any hidden extras. Like you, we want your project to be completed on budget and on time, meeting all legal requirements.