Annexe extensions in Colwyn Bay: design, approvals and build
Our design and build teams take on annexe extensions in Colwyn Bay, from the first measured survey through planning and building control to the finished room.
- Guide price in Colwyn BayFrom £51,000 inc VAT
- PlanningUsually a planning application
- Build time16–24 weeks on site
- Postcode districtsLL28, LL29
Is an annexe extension right for your house?
- Homes with a large side or rear garden
- Multi-generational families
- Relatives who need support close by
What should I budget for an annexe extension in Colwyn Bay?
Labour and material costs vary across the UK, so for Colwyn Bay we use our Wales factor (×0.93). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Colwyn Bay: £1,860 to £3,530 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Studio annexe 25 m² | £51,000 – £64,000 | £55,500 – £70,000 | £69,500 – £88,500 |
| One-bedroom annexe 35 m² | £65,000 – £81,500 | £78,000 – £98,000 | £97,500 – £124,000 |
| Larger annexe 45 m² | £83,500 – £105,000 | £100,000 – £126,000 | £125,500 – £159,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Local to Colwyn Bay
We cover Colwyn Bay and the postcode districts LL28, LL29. Neighbouring towns we cover include Llandudno (5 miles), Rhyl (10 miles), Prestatyn (13 miles), Flint (25 miles).
In Wales, terraced houses with rear offshoots are common in the towns, while detached houses and bungalows dominate in rural areas.
Do I need planning permission in Colwyn Bay?
In Wales an annexe linked to the house and used by your household is assessed as an extension, but its size usually means a planning application is needed.
Homes in conservation areas, national parks, National Landscapes (AONBs) 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 before the foundations go in.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
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
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Your questions about an annexe extension in Colwyn Bay
Will my neighbours in Colwyn Bay be involved?
If a planning application is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do I need building regulations approval in Colwyn Bay?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Do you cover all of Colwyn Bay?
Yes. We cover Colwyn Bay and the surrounding parts of Clwyd. Site visits are free and there is no obligation.
Does an annexe extension need planning permission?
Usually yes, because of its size and the way it will be used. Councils check that it stays ancillary to the main house, so the application must describe the use clearly.
Can the annexe have its own front door?
Yes, many do, but it should still connect to the main house to stay clearly part of it.
Book a free site visit in Colwyn Bay
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.