Timber frame extensions in Gwynedd
Our design and build teams take on timber frame extensions in Gwynedd, from the first measured survey through planning and building control to the finished room.
- Guide priceFrom £19,500 inc VAT
- PlanningWelsh permitted development rules (rear up to 4 m)
- Towns covered4
- Site visitFree, no obligation

Towns in Gwynedd
Will the council need to approve it?
In Wales a single-storey rear extension can usually project up to 4 m beyond the rear wall without a planning application, if it is no more than 4 m high, keeps eaves to 3 m and overall height to 4 m within 2 m of a boundary, and covers no more than half the land around the original house. Wales has no larger home extension prior approval scheme.
The planning position for a specific Gwynedd 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 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).
Who a timber frame extension suits
- Homeowners who want strong energy performance
- Contemporary designs with timber or board cladding
- Sites where weight or speed matters
Moisture is the enemy of any timber building. We design ventilated cladding cavities, breather membranes and a proper damp-proof course height, and keep the frame dry during construction.
Extensions in and around Gwynedd
Towns we cover in Gwynedd include Bangor, Gwynedd, Caernarfon, Holyhead, Llangefni. In Wales, terraced houses with rear offshoots are common in the towns, while detached houses and bungalows dominate in rural areas.
How much does a timber frame extension cost in Gwynedd?
Prices below are for Gwynedd, using the Wales factor of ×0.93. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Gwynedd: £1,630 to £3,160 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £19,500 – £23,500 | £22,500 – £30,000 | £29,000 – £38,000 |
| 4 m × 5 m 20 m² | £32,500 – £39,500 | £38,000 – £49,500 | £48,000 – £63,500 |
| 5 m × 6 m 30 m² | £48,500 – £59,000 | £57,000 – £74,000 | £72,500 – £95,000 |
Try the guide-price tool to see a range for your own size and finish.
Our process, step by step
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
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 Gwynedd
How long does a timber frame extension take to build in Gwynedd?
On site, typically 8 to 14 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
Will my neighbours in Gwynedd 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.
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.
Does a timber frame extension need planning permission?
The same planning rules apply as for any extension. If the cladding looks different from the house, permitted development’s matching-materials condition may mean an application is needed.
Is timber frame cheaper than brick?
It is similar overall. The frame can save time on site, but the cladding choice has a big effect on cost. Our guide range is about £1,630 to £3,160 per m² including VAT.
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.