Building regulations for extensions in West Sussex
We prepare building regulations for extensions for homes across West Sussex, on their own or as the first stage of a full design and build project.
- Guide priceFrom £1,000 inc VAT
- Approval routeFull plans or building notice
- Towns covered12
- Site visitFree, no obligation
Towns in West Sussex
Working in West Sussex
Towns we cover in West Sussex include Crawley, Worthing, Bognor Regis, Littlehampton, Horsham, Haywards Heath, Chichester, Burgess Hill. In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
Planning and approvals in West Sussex
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
What it costs in West Sussex
Fees below are our West Sussex guide (×1.12, the South East England factor), including VAT. Council and building control fees are extra.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Building regulations drawings for a simple single-storey extension | £1,000 – £2,050 |
| Standard | Drawings plus structural calculations | £1,450 – £2,950 |
| Premium | Complex or two-storey pack with energy calculations | £2,450 – £4,300 |
Our design fee only. Building control charges are set by your council (or, in England and Wales, a registered building control approver) and quoted separately.
Want a range for your exact size? The guide-price tool takes about a minute.
When it helps
- Glass-heavy designs that need energy calculations
- Every extension, whatever the planning route
- Homeowners using their own builder who need the drawings
How the project works
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
We visit your West Sussex home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Common questions in West Sussex
Do I need building regulations approval in West Sussex?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How long does this take for a West Sussex home?
2–5 weeks for drawings, depending on the council and the complexity of the project.
Do you cover all of West Sussex?
Yes, across the whole of West Sussex. Site visits are free and there is no obligation.
What are the insulation standards for an extension?
In England, new walls in an extension should achieve a U-value of 0.18 W/m²K, roofs 0.15 and floors 0.18, with windows at 1.4 and rooflights at 2.2. Wales, Scotland and Northern Ireland set their own figures.
Who are building control?
Either your local council’s building control team or a registered building control approver. Both inspect the work and issue the completion certificate.
Book a free site visit in West Sussex
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.