Side return extensions in Boston: design, approvals and build
Thinking about a side return extension for your Boston home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide price in BostonFrom £17,000 inc VAT
- PlanningOften permitted development; party wall notice usual
- Build time10–14 weeks on site
- Postcode districtsPE21
Local to Boston
Postcode districts we cover around Boston include PE21. We also work in nearby Spalding (14 miles), Skegness (19 miles), Grantham (26 miles), Lincoln (27 miles).
For homes towards Cambridgeshire, Wisbech is around 23 miles away. Homes across the East Midlands often have usable side land or a driveway beside the house, which opens up side and wraparound options.
Guide prices for Boston
Labour and material costs vary across the UK, so for Boston we use our East Midlands factor (×0.95). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Boston: £2,000 to £3,610 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 1.8 m × 4.5 m 8 m² | £17,000 – £20,500 | £18,000 – £23,000 | £22,500 – £29,000 |
| 2 m × 5.5 m 11 m² | £21,500 – £26,500 | £25,000 – £31,500 | £31,000 – £40,000 |
| 2.2 m × 7 m 15 m² | £29,500 – £36,000 | £34,000 – £43,000 | £42,500 – £54,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Planning and approvals in Boston
In England a single-storey side return infill is often permitted development if it stays within the height limits and is no wider than half the width of the original house. Conservation areas, listed buildings and flats always need an application, and the boundary wall usually brings in the Party Wall Act.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
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.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
What we take care of
- Glazed, sloping or flat roof with rooflights
- Kitchen-ready shell or full finish
- Survey of the outrigger, boundary wall and drainage
- Party wall notice support (England and Wales)
- New boundary wall or raised party wall
- Removal of the side wall and new steelwork
Light is the design problem. A side return can make the middle of the house darker if the roof is solid, so we model the daylight and usually recommend a glazed slope or a run of rooflights along the boundary edge.
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 draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
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 a side return extension in Boston
How long does a side return extension take to build in Boston?
On site, typically 10 to 14 weeks once approvals are in place. Before that, allow 6–12 weeks design and approvals.
Do you cover all of Boston?
Yes. We cover Boston and the surrounding parts of Lincolnshire. 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 Boston, 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 side return extensions need planning permission?
In England many single-storey side returns fit within permitted development if they stay within the height limits and are no wider than half the width of the original house. Conservation areas, listed buildings and flats need an application. Other UK nations have their own rules, which we check.
How much does a side return extension cost?
Our guide range is about £2,000 to £3,610 per m² including VAT, so a typical 2 m × 5.5 m infill lands around £25,000 to £31,500 at standard spec in Boston, more in London.
Book a free site visit in Boston
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.