🏗️ Rear Extension Specialists

Rear Extensions London

Extend into your garden to create the open-plan kitchen, dining and family space your home is missing. In-house architects, structural engineers and build teams deliver your rear extension end to end across North West London.

✓ Planning Managed✓ Party Wall Handled✓ 10-Year Warranty✓ RIBA Architects

More Living Space, Straight Off the Back of Your Home

A rear extension projects outward from the back wall of your house into the garden. It is the most direct way to enlarge a kitchen, create an open-plan living area, or add a ground-floor utility or family room. Single-storey rear extensions suit most terraced, semi-detached and detached houses; a double-storey rear extension adds a bedroom or bathroom above. We handle design, planning, structural engineering, party wall and construction under a single contract.

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Open-Plan Kitchen-Diners

The most popular use of a rear extension is to merge the kitchen, dining and family space into one bright, garden-facing room, often with bi-fold or sliding doors and a roof lantern.

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Often Permitted Development

Many single-storey rear extensions can be built under Permitted Development rights without a full planning application — we assess this for every property before you commit.

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Single or Double Storey

Add space on the ground floor alone, or build a two-storey rear extension to gain an extra bedroom or bathroom above the new kitchen or living room.

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Structural Engineering In-House

Removing the original rear wall needs steel beams, padstones and often new foundations. Our in-house structural engineer designs and certifies every element.

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Party Wall Managed

Where work affects a shared boundary or requires excavation near a neighbour, we coordinate the Party Wall etc. Act 1996 notices and surveyors on your behalf.

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Adds Space and Value

A well-designed rear extension adds usable square footage and is consistently one of the most sought-after features for buyers in the North London market.

Rear Extension Timescales

Programmes vary with size, ground conditions, glazing and kitchen specification. The figures below are indicative on-site durations; we issue a detailed programme and a fixed, itemised quotation after a site survey.

Project TypeIndicative Timeline (on site)Typical Scope
Small single-storey rear10–14 weeksStructure, roof, glazing, finishes
Large single-storey / open-plan14–20 weeksExtension plus new kitchen and knock-through
Double (two-storey) rear18–26 weeksGround + first floor, new room above
Rear extension + internal remodel20–30 weeksExtension with wider ground-floor reconfiguration

Every project is priced individually. Use our cost calculator or book a free consultation for a detailed, fixed quotation.

How We Deliver Your Rear Extension

1

Free Site Survey & Consultation

An architect visits, measures the rear of your property, reviews the structure and discusses your brief and budget — no obligation.

2

Design, Planning or Lawful Development

We produce drawings and 3D visuals, then submit either a Lawful Development Certificate (for Permitted Development) or a full householder planning application, whichever your property requires.

3

Structural Engineering & Building Regulations

Our structural engineer designs the steelwork and foundations and we obtain Building Regulations approval, liaising with the inspector throughout.

4

Party Wall & Construction

We serve any required party wall notices, then our directly-employed build team carries out groundworks, structure, roofing, glazing and finishes under a dedicated project manager.

5

Kitchen, Finishes & Handover

We install the kitchen, joinery, flooring and decoration, then hand over with your Building Regulations Completion Certificate and 10-year structural warranty.

Rear Extension Case Studies

We are adding photographed, costed case studies for this service. To see comparable completed schemes, book a consultation or browse our case study portfolio.

Rear Extension FAQs

How far can a rear extension project under Permitted Development?
As of 2026, under the Permitted Development rules published on the Planning Portal, a single-storey rear extension can typically extend up to 3m from the original rear wall for a terraced or semi-detached house (4m for a detached house). Under the Larger Home Extension prior-approval scheme this can rise to 6m (8m detached), subject to a neighbour consultation. Maximum height is generally 4m. Properties in conservation areas or under an Article 4 Direction usually lose some or all of these rights. We assess your specific property before any work begins.
Do I need planning permission for a rear extension?
Not always. Many single-storey rear extensions fall within Permitted Development and only need a Lawful Development Certificate. Larger, two-storey, or conservation-area extensions usually need a full householder planning application (typically determined within about 8 weeks). We confirm the correct route for your home at the survey stage.
Will I need a party wall agreement?
If the extension is built up to or astride a shared boundary, or involves excavation within 3–6m of a neighbouring structure, the Party Wall etc. Act 1996 applies and notice must be served. We manage the notices and any surveyor appointments for you.
Can I stay in my home during the build?
In most cases yes. Rear extension work is largely external in the early phases; we phase the kitchen knock-through to minimise disruption and discuss a practical plan with you before starting.
How long does a rear extension take?
A typical single-storey rear extension takes around 10–20 weeks on site depending on size and specification, plus an earlier 8–12 week design and approvals phase. We provide a detailed programme up front.
What areas do you cover?
We build rear extensions across North West and North London, including Hampstead, Belsize Park, Camden, Highgate, Muswell Hill, West Hampstead, St John's Wood and surrounding areas.

Ready to Plan Your Rear Extension?

Book a free, no-obligation consultation. Our architects will visit, assess what is achievable on your property, and provide a transparent, fixed quotation.

Chat with us!