A single-storey extension is a new ground-floor room built onto your house, usually at the rear or side, with its own foundations, walls and roof, creating a bigger kitchen, living space or bedroom without moving home.
Every house in Formby is a little different, so we never price a single-storey extension from a brochure. We look at the structure, access and existing finishes first, then put in writing a fixed figure for the scope we settle on. As a rough steer, homeowners in the North West should budget £33,000–£71,000 including VAT, with work typically taking 10–16 weeks on site.
- Guide price
- £33,000–£71,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- L37
- Planning rules
- England
- Local area
- Sefton
- Survey
- Free, with a written quote
What should you budget for a single-storey extension in Formby?
Budgeting for a single-storey extension in Formby? The numbers below include VAT and are adjusted for the North West, where costs are about 5% below the national guide. The headline range is £33,000–£71,000. Nothing is final until we have measured up at a free survey and agreed the specification with you.
| Type of job | What it usually involves | Guide in Formby |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £21,000–£38,000 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £33,000–£71,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £66,000–£124,000 |
Your price depends mostly on:
- Floor area, shape and number of corners
- Roof type, rooflights, lanterns and the amount of glazing
- Ground conditions, foundation depth and drains to divert
- Steelwork needed to open into the existing house
What do you get?
- Cavity walls built and insulated to building regulations
- Steel beams to open into the existing house
- Electrics and plumbing by qualified trades, with certificates
- Windows and external doors, including bifolds if chosen
- Plastering, screed floor and internal doors
- Building control inspections and completion certificate
Local housing and a single-storey extension
Liverpool's housing includes Georgian terraces near the centre, large areas of Victorian red-brick terraces, Edwardian semis in the suburbs and big interwar council estates. The Wirral has Victorian villas and interwar semis, Southport has Victorian villas and bungalows, and St Helens and Knowsley have post-war estates and newer housing.
Terraces suit loft rooms, kitchen extensions and repointing, and many need their roofs and windows renewed. Suburban semis commonly take side extensions, driveways and porches.
Knowing the typical building types in Merseyside helps, but a survey of your own home in Formby is what decides the right approach to a single-storey extension.
Planning and building rules in Formby
As Formby is in England, read the following with that system of planning and building control in mind. We check what applies to your house with the council before you receive a quote.
In England, many single-storey rear extensions are permitted development: typically up to 3 m deep on a semi-detached or terraced house and 4 m on a detached house, no more than 4 m high, and covering no more than half the land around the original house. Larger rear extensions can go through the prior approval process. Side extensions, flats, listed buildings, conservation areas and homes where permitted development rights have been removed need planning permission.
Building Regulations approval is needed for almost every extension, covering foundations, structure, insulation, drainage, ventilation and fire safety. If the work is on or near a shared wall or boundary, the Party Wall etc. Act 1996 may apply.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
From survey to handover
We look at the job
First, someone visits your home in Formby to see the space, take measurements and note anything that could affect the work, such as access or the condition of what is there. There is no charge for this visit.
Price and scope agreed
We put everything into a written, fixed-price quote: the specification, what's excluded, staged payments and the expected time on site. Take whatever time you need to decide; there's no pressure to commit.
Booking the work
Preparation matters as much as the build. We agree access, parking and working hours with you, order materials in good time, and confirm any permissions so the job isn't held up once it starts.
Build and hand over
Work goes ahead as scheduled and you deal with one contact throughout. When the last trade leaves, we clear and clean the site, talk you through what has been done and pass on any certificates and care instructions.
Working with SK Home Improvements
Single-storey extensions in Formby: questions
What is the Party Wall Act and does it apply to me?
The Party Wall etc. Act 1996 applies in England and Wales only. In England and Wales, it requires you to give notice to neighbours before certain work on or near a shared wall, such as digging foundations within 3m of their building and deeper than its footings. Neighbours can agree or appoint a surveyor. Scotland and Northern Ireland have no equivalent Act, though general rights still apply. We identify whether notices are needed during the survey.
Who do I deal with during the job?
One point of contact manages your project from survey to handover. They schedule the trades working under our contract, keep you updated on progress, and are the person to call with any question. You don't need to coordinate builders, electricians or decorators separately, because that is part of what we do.
How much does a single-storey extension cost?
A typical single-storey rear extension of 15–25m² costs £33,000–£71,000, built to a plastered finish ready for your kitchen and decoration. As a guide, allow roughly £1,600–£2,800 per square metre plus fixed costs for groundworks, steelwork and fees. Smaller extensions cost more per square metre. The kitchen, flooring and large glazed doors are usually the biggest extras. We confirm a fixed price for the agreed specification after the survey.
Do I need planning permission for a single-storey extension?
Whether you need planning permission depends on the extension's size and height, how close it is to boundaries, your home's location, whether it is listed or in a conservation area, and which UK nation you live in. In England, many rear extensions up to 3m deep on a semi or terrace, or 4m on a detached house, can be built under permitted development. We check the rules that apply to your home before quoting.
Which postcodes in Formby do you cover?
We cover L37, along with the rest of Merseyside. If your postcode is not listed, get in touch anyway: our coverage is UK-wide, and we can usually arrange a survey wherever you live. Enter your postcode in the guide-price tool or contact form and we will confirm.
Also covering areas around Formby
Homes across L37 in Formby are within our coverage, as are those in Maghull, Southport and Bootle. If you are just outside these areas, ask anyway, because we work right across the UK.