Timber frame extensions in Belfast: design, approvals and build
We design and build timber frame extensions for houses in Belfast, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in BelfastFrom £18,000 inc VAT
- PlanningNI permitted development (rear 3–4 m) or planning
- Build time8–14 weeks on site
- Postcode districtsBT1, BT2, BT6, BT7, BT12

Will the council need to approve it?
In Northern Ireland the Planning (General Permitted Development) Order 2015 lets some single-storey rear extensions go ahead without planning permission, up to 3 m on a semi-detached or terraced house and 4 m on a detached house, within height and boundary limits. Larger, side and two-storey extensions normally need planning permission from the council, and building control approval is separate.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Northern Ireland has no Party Wall Act. Where work is on or close to a shared boundary, we agree access and protection with your neighbour in writing before work starts.
Applications are decided by your council, which handles local planning in Northern Ireland.
Working in Belfast
Across BT1, BT2, BT6, BT7, BT12, BT13, we can visit, measure and advise. Neighbouring towns we cover include Castlereagh (2 miles), Newtownabbey (4 miles), Lisburn (7 miles), Carrickfergus (10 miles).
For homes towards County Down, Newtownards is around 9 miles away. In Northern Ireland, extension projects follow the NI planning rules and council building control, which we account for from the first survey.
When a timber frame extension makes sense
- Contemporary designs with timber or board cladding
- Sites where weight or speed matters
- Homeowners who want strong energy performance
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.
How much does a timber frame extension cost in Belfast?
These guide figures apply our Northern Ireland adjustment (×0.86) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Belfast: £1,500 to £2,920 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £18,000 – £22,000 | £21,000 – £27,500 | £26,500 – £35,500 |
| 4 m × 5 m 20 m² | £30,000 – £36,500 | £35,000 – £46,000 | £44,500 – £58,500 |
| 5 m × 6 m 30 m² | £45,000 – £54,500 | £52,500 – £68,500 | £67,000 – £88,000 |
Want a range for your exact size? The guide-price tool takes about a minute.
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
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
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions people ask about timber frame extensions
Who do I contract with for a timber frame extension in Belfast?
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 you cover all of Belfast?
Yes. We cover Belfast and the surrounding parts of County Antrim. Site visits are free and there is no obligation.
How long does a timber frame extension take to build in Belfast?
On site, typically 8 to 14 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
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 £1,500 to £2,920 per m² including VAT.
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.
Book a free site visit in Belfast
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.