Side extensions across Swanage
We design and build side extensions for houses in Swanage, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in SwanageFrom £22,000 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsBH19
Side extension prices in Swanage
Labour and material costs vary across the UK, so for Swanage we use our South West England factor (×1.02). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Swanage: £1,780 to £3,470 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £22,000 – £27,000 | £25,000 – £32,500 | £31,500 – £42,000 |
| 3 m × 6 m 18 m² | £32,000 – £39,000 | £37,500 – £49,000 | £47,500 – £62,500 |
| 3 m × 8 m 24 m² | £42,500 – £51,500 | £50,000 – £65,000 | £63,500 – £83,500 |
Try the guide-price tool to see a range for your own size and finish.
Extensions in and around Swanage
Postcode districts we cover around Swanage include BH19. We also work in nearby Poole (7 miles), Bournemouth (9 miles), Christchurch (12 miles), Ferndown (14 miles).
In the South West, local stone, render and brick vary from town to town, so matching materials is a big part of designing an extension that looks right.
Planning rules that apply in Swanage
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
The planning position for a specific Swanage address depends on its history and any designations, which is why we check it at the first visit.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
What we take care of
- Foundations near boundaries and any drains
- New openings through the side wall
- Windows, doors and finishes to match
- Survey, design and street-view drawings
- Structure, roof tied into the house
Councils often prefer side extensions to sit slightly back from the front of the house with a lower roof, so the original building still reads clearly. We design to those principles from the start to avoid redesigns.
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
We visit your Swanage home, measure up, talk through what you want and check the planning position.
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
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Your questions about a side extension in Swanage
Will my neighbours in Swanage be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do you cover all of Swanage?
Yes. We cover Swanage and the surrounding parts of Dorset. 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 Swanage, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How much does a side extension cost?
Our guide range is about £1,780 to £3,470 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £37,500 to £49,000 in Swanage.
Can I build a side extension without planning permission?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a planning application.
Book a free site visit in Swanage
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.