Planning permission for extensions in Sunbury-on-Thames
Need planning permission for extensions in Sunbury-on-Thames? We survey the house, prepare what the council needs and deal with the officers until a decision is made.
- Guide price in Sunbury-on-ThamesFrom £350 inc VAT
- PlanningWe find the right route for you
- Timescale8–13 weeks typical decision period
- Postcode districtsKT12, TW16, TW17
Fees in Sunbury-on-Thames
Fees below are our Sunbury-on-Thames guide (×1.12, the South East England factor), including VAT. Council and building control fees are extra.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Permitted development confirmed in writing (certificate or notification) | £350 – £750 |
| Standard | Householder planning application handled | £650 – £1,250 |
| Premium | Application with heritage or design statements, and responses to the council | £1,000 – £1,800 |
Our handling fee only. Council fees are extra: in England from 1 April 2026 a householder application is £548, a lawful development certificate for a proposed extension £274 and a larger home extension prior approval £249. Drawings are priced separately.
Try the guide-price tool to see a range for your own size and finish.
Local to Sunbury-on-Thames
We cover Sunbury-on-Thames and the postcode districts KT12, TW16, TW17. Nearby, we also take on projects in Walton-on-Thames (1 mile), West Molesey (2 miles), Ashford, Surrey (3 miles), Weybridge (3 miles).
For homes towards Greater London, Hampton is around 2 miles away. In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
Who this service is for
- Homeowners who would rather not deal with the council themselves
- Anyone unsure whether their extension needs permission
- Projects in conservation areas or with previous refusals
Planning rules that apply in Sunbury-on-Thames
In England the main routes are permitted development (ideally confirmed with a lawful development certificate, £274), larger home extension prior approval (£249, 42 days) and a householder planning application (£548, normally 8 weeks), with council fees as set from 1 April 2026.
The planning position for a specific Sunbury-on-Thames address depends on its history and any designations, which is why we check it at the first visit.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
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).
From first visit to completion
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 Sunbury-on-Thames home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions answered
Who do I contract with in Sunbury-on-Thames?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do I need building regulations approval in Sunbury-on-Thames?
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 Sunbury-on-Thames home?
8–13 weeks typical decision period, depending on the council and the complexity of the project.
What happens if planning is refused?
You can revise the design and reapply, or appeal. We read the officer’s report and tell you honestly which option has a better chance.
How much does planning permission cost?
In England, from 1 April 2026 the council fee is £548 for a householder application, £274 for a lawful development certificate for a proposed extension and £249 for larger home extension prior approval. Our handling fee is separate.
Book a free site visit in Sunbury-on-Thames
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.