Planning permission for extensions in Caernarfon
Need planning permission for extensions in Caernarfon? We survey the house, prepare what the council needs and deal with the officers until a decision is made.
- Guide price in CaernarfonFrom £300 inc VAT
- PlanningWe find the right route for you
- Timescale8–13 weeks typical decision period
- Postcode districtsLL55

Working in Caernarfon
Postcode districts we cover around Caernarfon include LL55. Nearby, we also take on projects in Bangor, Gwynedd (7 miles), Llangefni (10 miles), Holyhead (19 miles).
Just over the Clwyd border, Llandudno is about 20 miles away. In Wales, terraced houses with rear offshoots are common in the towns, while detached houses and bungalows dominate in rural areas.
When it helps
- Anyone unsure whether their extension needs permission
- Projects in conservation areas or with previous refusals
- Homeowners who would rather not deal with the council themselves
Fees in Caernarfon
Fees below are our Caernarfon guide (×0.93, the Wales 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) | £300 – £650 |
| Standard | Householder planning application handled | £550 – £1,050 |
| Premium | Application with heritage or design statements, and responses to the council | £800 – £1,500 |
Our handling fee only. Council fees are extra and are set by the Welsh Government. Drawings are priced separately.
Try the guide-price tool to see a range for your own size and finish.
Will the council need to approve it?
In Wales the routes are permitted development (a lawful development certificate is available), or a householder planning application to the council. Wales has no prior approval scheme for larger rear extensions, and fees are set by the Welsh Government.
The planning position for a specific Caernarfon address depends on its history and any designations, which is why we check it at the first visit.
The Party Wall etc. Act 1996 applies in Wales as in England: notice must be served before work to a shared wall, building on the boundary, or excavating close to a neighbour's foundations.
Building regulations approval is separate from planning. Wales has its own building regulations and approved documents; the council or a registered building control approver checks the plans, inspects the work and issues a completion certificate.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
What happens next
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Common questions in Caernarfon
Do I need building regulations approval in Caernarfon?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Do you cover all of Caernarfon?
Yes. We cover Caernarfon and the surrounding parts of Gwynedd. Site visits are free and there is no obligation.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Caernarfon, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
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.
Book a free site visit in Caernarfon
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.