Single-storey rear extensions in Muswell Hill: design, approvals and build
From the first sketch to final sign-off, we plan and build single-storey extensions in Muswell Hill and the surrounding Greater London area.
- Guide price in Muswell HillFrom £27,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsN2, N6, N8, N10, N11
Planning and approvals in Muswell Hill
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.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
How much does a single-storey extension cost in Muswell Hill?
Labour and material costs vary across the UK, so for Muswell Hill we use our London factor (×1.3). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Muswell Hill: £2,280 to £4,420 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £27,000 – £32,000 | £31,500 – £41,000 | £40,500 – £53,500 |
| 4 m × 5 m 20 m² | £45,500 – £53,500 | £53,000 – £68,000 | £67,500 – £88,500 |
| 5 m × 6 m 30 m² | £68,000 – £80,000 | £79,500 – £101,500 | £101,000 – £133,000 |
Try the guide-price tool to see a range for your own size and finish.
Working in Muswell Hill
Our survey diary covers Muswell Hill, including N2, N6, N8, N10, N11, N22. Nearby, we also take on projects in Wood Green (1 mile), Friern Barnet (2 miles), Harringay (2 miles), Palmers Green (2 miles).
Just over the Hertfordshire border, Potters Bar is about 7 miles away. In London, space is at a premium and gardens are often short, so side returns, wraparounds and carefully planned rear extensions tend to make the most of every metre.
Who a single-storey extension suits
- Semi-detached and detached houses with a usable rear garden
- Homeowners who want open-plan living onto the garden
- Terraced houses that want a deeper kitchen across the full width
Depth is the big decision. Every extra metre adds floor area but also takes garden and can push you out of permitted development. We draw the room at two or three depths so you can see the trade-off in space, light and cost before anything is fixed.
Our process, step by step
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
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
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions people ask about single-storey extensions
Do you cover all of Muswell Hill?
Yes. We cover Muswell Hill and the surrounding parts of Greater London. Site visits are free and there is no obligation.
Who do I contract with for a single-storey extension in Muswell Hill?
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.
How long does a single-storey extension take to build in Muswell Hill?
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 Muswell Hill
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.