Expanding your home through a rear extension is one of the most effective ways to enhance both space and value without the disruption of moving. At Standley Design & Build, we specialise in delivering bespoke rear extensions across South West London — combining architectural precision, build quality, and seamless project management.
Whether your goal is to open up a kitchen-diner, introduce more natural light, or create additional living space, a well-designed rear extension can transform the way you live. In this guide, we explain what a rear extension involves, the permissions required, cost considerations, and how our integrated design-and-build approach ensures an exceptional outcome.
Understanding Rear Extensions
A rear extension involves extending your property outwards from the rear elevation — typically into garden space — to increase the internal floor area. It is one of the most flexible and popular types of home extension, especially in London, where expanding outward is often more practical than building upward.
Homeowners choose rear extensions for a variety of reasons, including:
- Optimising layout and flow: Create open-plan living spaces that suit contemporary lifestyles.
- Enhancing natural light: Incorporate skylights, sliding or bi-fold doors to flood interiors with light.
- Avoiding the cost of moving: Adapt your current home to meet your needs instead of relocating.
- Increasing property value: Quality extensions can significantly boost market value and desirability.
At Standley Design & Build, we ensure that every extension feels like a natural continuation of your home — architecturally coherent, structurally sound, and built to last.
Types of Rear Extensions
The right extension depends on your property type, budget, and long-term objectives. The most common configurations include:
1. Single-Storey Rear Extension
The most straightforward and cost-effective option, ideal for enlarging kitchens, dining areas, or family rooms. This approach focuses on maximising light and flow while maintaining strong visual connections to the garden.
2. Double-Storey Rear Extension
A more substantial option that extends both ground and first floors, providing additional bedrooms, bathrooms, or office space above the new ground-floor footprint. Although more complex, this design can offer exceptional functionality and value.
3. Wraparound or L-Shaped Extension
By combining side and rear extensions, this configuration unlocks potential in awkward or narrow plots — a popular solution for London’s terraced homes. It allows for dynamic layouts and generous open-plan interiors.
Each design is tailored by our in-house architectural team to respect the existing structure while optimising the use of space and light.
Planning Permission and Regulations
A common question among homeowners is whether planning permission is required for a rear extension. The answer depends on several factors, including the size, height, and location of the proposed build.
Permitted Development Rights
Many single-storey rear extensions fall under permitted development (PD), meaning full planning permission is not required if certain conditions are met. For example:
- The extension must not exceed 4 metres in height.
- Detached homes may extend up to 4 metres beyond the original rear wall; semi-detached and terraced homes are typically limited to 3 metres (or more under prior approval).
- Materials should be consistent with the existing property.
- Roof design and placement of windows must protect neighbouring privacy.
If your property lies within a conservation area, or if the proposal exceeds PD limits, householder planning permissionwill be required.
Building Regulations
Regardless of planning status, all extensions must comply with Building Regulations. These govern critical aspects such as structural stability, insulation, drainage, and fire safety. Our design and engineering teams prepare all required technical drawings and liaise with Building Control to ensure full compliance.
Party Wall and Neighbour Consultation
If your property adjoins another, the Party Wall Act 1996 may apply. We manage the entire process — including notices and agreements — to ensure the project proceeds smoothly and professionally.
Cost and Timeline Considerations
Every rear extension is unique, and costs vary according to size, specification, and complexity. In South West London, typical build costs range between £1,900 and £3,000 per square metre, depending on materials, glazing, finishes, and access constraints.
Key factors influencing cost include:
- Size and structure: Double-storey or steel-frame designs require more engineering.
- Glazing and finishes: Large-format glazing, bespoke joinery, and high-end interiors raise overall costs.
- Ground conditions: Poor soil or restricted access can increase foundation and labour costs.
- Professional services: Architectural design, structural calculations, and Building Control approvals form part of the total investment.
A well-planned project typically follows this timeline:
- Feasibility & Design: 4–8 weeks
- Planning & Approvals: 8–12 weeks (if required)
- Pre-construction & Procurement: 2–4 weeks
- Construction & Fit-Out: 12–20 weeks
From concept to completion, most projects are completed within 7–15 months, depending on scope and approvals.
The Standley Design & Build Approach
As a fully integrated design-and-build company, Standley Design & Build offers a single point of responsibility for every aspect of your extension. Our process is structured, transparent, and client-centred.
1. Consultation & Site Assessment
We begin with an on-site meeting to understand your objectives, assess your property, and identify design opportunities and planning considerations.
2. Concept & Feasibility Design
Our architects produce tailored design options, visualising how space, light, and circulation can be optimised to suit your lifestyle.
3. Detailed Design & Planning Submission
We handle all technical documentation, planning applications, and structural coordination, ensuring compliance and accuracy from the outset.
4. Construction & Project Delivery
Our in-house build team manages all site operations with meticulous attention to detail, ensuring quality workmanship and adherence to timelines.
5. Completion & Aftercare
We carry out full inspections, quality assurance, and handover documentation, providing peace of mind long after completion.
Our cohesive design-and-build model minimises risk, reduces delays, and ensures continuity of quality from concept through construction.
Common Pitfalls to Avoid
Through our years of experience across South West London, we’ve identified several common pitfalls homeowners should avoid:
- Assuming permitted development applies — Always verify eligibility before construction.
- Underestimating costs — Build in a contingency of 10–15% for unforeseen conditions.
- Ignoring design coherence — Seamless integration between old and new is crucial for aesthetics and resale value.
- Neglecting neighbour relations — Early communication avoids unnecessary disputes.
- Cutting corners on insulation or structure — Quality here ensures comfort, efficiency, and longevity.
By engaging a professional design-and-build team from the outset, you safeguard your investment and ensure a result that enhances both function and beauty.
Transforming Homes Across South West London
From compact kitchen extensions to expansive two-storey additions, Standley Design & Build has transformed homes throughout South West London. Our projects consistently balance innovation, craftsmanship, and respect for architectural context.
Every build reflects our core principles — quality, transparency, and professionalism. We pride ourselves on creating spaces that not only meet today’s needs but also stand the test of time.
Begin Your Project
If you are considering a rear extension, we invite you to arrange a no-obligation consultation with our team. We will assess your property, explore design options, and provide clear guidance on planning, budget, and next steps.
Contact Standley Design & Build today to discover how we can help you transform your home through intelligent design and exceptional craftsmanship.