Single-storey rear extensions in Merseyside
Planning a single-storey extension in Merseyside? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide priceFrom £19,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Towns covered17
- Site visitFree, no obligation

Towns in Merseyside
How much does a single-storey extension cost in Merseyside?
For Merseyside 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 Merseyside: £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 |
Want a range for your exact size? The guide-price tool takes about a minute.
Working in Merseyside
Towns we cover in Merseyside include Liverpool, Birkenhead, St Helens, Southport, Wallasey, Bootle, Bebington, Huyton. Across the North West, terraced houses with small rear yards suit compact rear and side return extensions, while suburban semis have room for more.
Will the council need to approve it?
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.
The planning position for a specific Merseyside address depends on its history and any designations, which is why we check it at the first visit.
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).
Is a single-storey extension right for your house?
- Semi-detached and detached houses with a usable rear garden
- Terraced houses that want a deeper kitchen across the full width
- Homeowners who want open-plan living onto the garden
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
We visit your Merseyside 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
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Your questions about a single-storey extension in Merseyside
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Merseyside, 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 you cover all of Merseyside?
Yes, across the whole of Merseyside. Site visits are free and there is no obligation.
Will my neighbours in Merseyside 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.
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.
How much does a single-storey extension cost per square metre?
Our guide range is about £1,660 to £3,230 per m² including VAT, depending on specification. A standard-spec 4 m × 5 m room usually lands at £38,500 to £49,500 in Merseyside, plus design and council fees.
Book a free site visit in Merseyside
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.