Single-storey rear extensions in Formby: design, approvals and build
Our design and build teams take on single-storey extensions in Formby, from the first measured survey through planning and building control to the finished room.
- Guide price in FormbyFrom £19,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsL37
Working in Formby
Our survey diary covers Formby, including L37. Nearby, we also take on projects in Maghull (6 miles), Southport (7 miles), Bootle (7 miles), Litherland (7 miles).
Ormskirk, in Lancashire, is roughly 8 miles from Formby 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 is included
- Flat or pitched roof, rooflights or lantern
- Building regulations drawings and structural calculations
- Planning route checked and the right approval obtained
- Foundations, drainage and groundworks
- Measured survey and design
- Doors, windows, insulation, plastering and first fix to finish
How much does a single-storey extension cost in Formby?
These guide figures apply our North West England adjustment (×0.95) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Formby: £1,660 to £3,230 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £19,500 – £23,500 | £23,000 – £30,000 | £29,500 – £39,000 |
| 4 m × 5 m 20 m² | £33,000 – £39,000 | £38,500 – £49,500 | £49,000 – £65,000 |
| 5 m × 6 m 30 m² | £49,500 – £58,500 | £58,000 – £74,500 | £74,000 – £97,000 |
For a figure based on your own dimensions, use our guide-price tool.
Do I need planning permission in Formby?
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
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).
From first visit to completion
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 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.
Single-storey extension questions answered
Who do I contract with for a single-storey extension in Formby?
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 I need building regulations approval in Formby?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How long does a single-storey extension take to build in Formby?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
Can I stay in the house during the build?
Usually yes. Most of the work happens outside until the final weeks, when we open the rear wall. We plan that stage carefully and seal the opening with a temporary screen to keep dust down.
Will I need a steel beam?
Almost always. Opening up the rear wall to join the new room to the house needs a beam, usually steel, sized by a structural engineer. It is included in our quotes.
Book a free site visit in Formby
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.