Annexe extensions in Southport
We design and build annexe extensions for houses in Southport, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in SouthportFrom £52,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsPR8, PR9

Do I need planning permission in Southport?
In England an annexe that stays part of the household and connects to the house is assessed as an extension, but its size usually takes it beyond permitted development, so a householder application describing the ancillary use is the normal route.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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.
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).
Covering Southport
Our survey diary covers Southport, including PR8, PR9. We also work in nearby Formby (7 miles), Maghull (9 miles), Litherland (12 miles), Kirkby (12 miles).
Lytham St Annes, in Lancashire, is roughly 7 miles from Southport and also on our list. Across the North West, terraced houses with small rear yards suit compact rear and side return extensions, while suburban semis have room for more.
What we take care of
- Fire separation and alarms to building regulations
- Planning application describing ancillary use
- Design for accessibility: level thresholds, wider doors, walk-in shower
- Separate or shared heating and hot water
- Kitchenette, shower room and bedroom finish
Accessibility is cheaper to design in than to retrofit. Level access, a 900 mm door width, a level-access shower and space to turn a wheelchair can all be planned into the footprint for little extra cost.
What should I budget for an annexe extension in Southport?
For Southport we adjust our national guide rates by ×0.95, the factor we use for North West England. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Southport: £1,900 to £3,610 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Studio annexe 25 m² | £52,000 – £65,500 | £57,000 – £71,500 | £71,000 – £90,500 |
| One-bedroom annexe 35 m² | £66,500 – £83,500 | £79,500 – £100,000 | £99,500 – £126,500 |
| Larger annexe 45 m² | £85,500 – £107,000 | £102,500 – £128,500 | £128,000 – £162,500 |
For a figure based on your own dimensions, use our guide-price tool.
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
We visit your Southport home, measure up, talk through what you want and check the planning position.
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions people ask about annexe extensions
Do I need building regulations approval in Southport?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How long does an annexe extension take to build in Southport?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 10–16 weeks design and approvals.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Southport, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Will an annexe affect council tax?
It can. Some annexes are assessed separately for council tax, with discounts or exemptions in some cases when occupied by a relative. Check with the Valuation Office Agency (England and Wales), your local assessor (Scotland) or Land & Property Services (Northern Ireland).
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 Southport
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.