Planning permission for extensions in Gwynedd
We prepare planning permission for extensions for homes across Gwynedd, on their own or as the first stage of a full design and build project.
- Guide priceFrom £300 inc VAT
- PlanningWe find the right route for you
- Towns covered4
- Site visitFree, no obligation

Towns in Gwynedd
What it costs in Gwynedd
Guide fees for Gwynedd including VAT, using our Wales factor of ×0.93. Council and building control charges are not included.
| 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.
For a figure based on your own dimensions, use our guide-price tool.
Planning and approvals in Gwynedd
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
Included in a typical project
- Planning history and constraints check for your address
- Liaison with the planning officer
- Application forms, plans and supporting statements
- Submission and fee payment guidance
- Route recommendation in writing
A lawful development certificate is not compulsory for permitted development, but it is the cleanest proof that the extension was lawful when you come to sell. We usually recommend one.
Covering Gwynedd
Towns we cover in Gwynedd include Bangor, Gwynedd, Caernarfon, Holyhead, Llangefni. Welsh housing ranges from stone terraces in the valleys to render-and-slate houses and modern estates, and the Welsh planning rules differ from England's in several places.
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
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.
Common questions in Gwynedd
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Gwynedd, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do I need building regulations approval in Gwynedd?
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 Gwynedd 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.
Book a free site visit in Gwynedd
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.