Architects in Surrey for House Extensions & Planning Applications

Planning permission, architectural design and project management  delivered end-to-end by a multi-award-winning local team.

Residential Architects in Surrey: Design, Planning & Building Regulations

Planning approved by 11 Surrey Councils — 8 weeks standard decision.
Permitted Development: 3m terraced, 4m detached — Green Belt + AONB exceptions apply.
Full design, planning, and building regulations in one fixed fee.
Loft conversions available — Velux, dormer, and hip-to-gable options.
In-house structural engineer included — no separate specialist needed.
98% planning approval rate — including Green Belt + AONB applications.

Extension Architecture handles planning applications, house extensions, and loft conversions across Surrey — covering all 11 district councils including Woking, Guildford, Elmbridge, Mole Valley, and Reigate & Banstead. Most single-storey rear extensions qualify as Permitted Development (3m terraced / 4m detached). Council decisions take 8 weeks. Free quote in 60 seconds.

We only deliver excellence

42⁺

Projects completed in Surrey

2220 ⁺

Our total projects completed in London & Surrey

Locations in Surrey

Guildford • Woking • Reigate • Banstead • Esher • Cobham • Weybridge • Dorking • Epsom • Leatherhead • Camberley

Postcodes Served

GU1–GU5, KT10–KT13, RH1–RH6, TW18–TW20

Our Expertise

Planning Application Drawings
Council-ready drawings, fast

3D Visualisations
See it before building

Retrospective Planning
Fix unpermitted works

Building Regulation Drawings
Safe, compliant drawings

Commercial Development Consultancy
Change of use experts

Interior Design
Finishes inside out

Spatial Planning & Layout
Smarter room layouts

Feasibility Consultancy
Know what’s possible

Recent Architects Surrey Extension & Loft Conversion Projects

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Planning in Surrey: Green Belt, AONB & Conservation Areas

As one of the UK’s most well known counties Surrey is famous for its rich cultural history, its beautiful countryside and stunning unique architecture. Surrey is a beautiful mix of picturesque rolling hills, charming villages and a blend of classical english cottages, stately Georgian houses, and cutting edge eco friendly constructions. The mixed use of historic and modern styles in this landscape gives it a visually spectacular quality, but it complicates planning permissions due to the inherent historic element to some of the areas. Quite a few of Surrey’s buildings are protected, which is good given that you have to be careful how much innovation and how much tradition you blend into any architectural project.

Part of working with Extension Architecture means working alongside experts who know Surrey’s architectural legacy inside out. We recognize the necessity of countering the county’s original character with contemporary, functional designs. But our architects treat each project with the greatest of respect for Surrey’s rich and beautiful history, always seeking to make changes to complement, rather than detract from, the area.

Whether your home is in a quaint village, like Worcester Park and Chessington, or luxury living, as it may be in Cobham and Weybridge, or in a thriving town, such as Guildford and Esher, Extension Architecture will be with you through the process, from the earliest concept to finished project. We are experts at even the most complex planning permissions, and we deliver results that respect the land, the landscape, and the people who live there.

Varied housing stock in Surrey — Victorian, Edwardian, and 1930s properties.
Green Belt + AONB affects some properties — always verify your address first.
Strong property values — well-designed extensions consistently add value.
Surrey's 11 district and borough councils each run their own planning policies, with a standard 8-week decision target.

What Our Clients Say About
Extension Architecture

Interior fit-out, Surrey

Architectural Services in Surrey: Planning Applications & Extensions

Many homeowners in Surrey prefer to expand their properties, most of the time by having loft extensions, building an additional floor, or carrying out big refurbishment. They are commonly looking to improve their home’s value as well as increasing day to day comfort without the inconvenience of purchasing a new one. But planning permissions in Surrey can be tricky to navigate, since Surrey has so many conservation areas designated to keep its important architectural character.

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Before & After: Surrey House Extension Projects

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Before

After

Why Choose Our Surrey Architects?

Our experienced team of Surrey architects will take the lead and create a thoughtful design that maximizes the available space and is tailored to your tastes. We will guide you through the intricacies of the planning process and discuss every aspect of the project in detail. Our architects will carefully survey your property to ensure no detail is overlooked. We will be with you throughout the process, providing clear and comprehensive instructions while walking you through the planning, application and construction process.

One-Stop Solution

Our firm provides a comprehensive range of services under one roof, from planning and architectural design to intricate interior and immersive design, and expertly manages the complexities of the construction process. We have delivered projects of various scales and budgets, from small home extensions to large new builds, for a diverse clientele.

In-house Structural Engineer

We have a structural engineer in-house - something most architecture firms don't offer. It matters because juggling separate specialists costs time and money. With a structural engineer on our team, calculations and drawings stay coordinated under one roof, keeping the design-build process smooth and reducing errors.

Interior Design + Architecture

Our team includes interior designers who work closely with every client to curate spaces tailored to their taste and how they live. This covers the enjoyable but important decisions - wall finishes, colour schemes, soft furnishings and flooring. Having architects and interior designers under one roof means fewer gaps and inconsistencies.

Turn-Key Approach

We provide support throughout the entire building process, embracing a ‘turnkey approach’ to ensure a smooth and efficient project from start to finish. Additionally, we assist in reducing build costs by aiding in the procurement of all internal fit-outs, including sanitaryware, kitchens, and more. It’s a zero hassle solution for clients.

Start Your Surrey Loft Conversion or House Extension Today

Thinking about extending your Surrey home? Our architects can help you make the most of your space, from the first design ideas to the final build.

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Years of Experience

17

Any Questions?

Didn’t find your answer? Feel free to reach out

Usually not. Most single-storey rear extensions in Surrey come under Permitted Development, so you can build without a full application — up to 4m for a detached house, 3m for terraced or semi-detached. If your home’s in the Green Belt, an AONB, or a conservation area, or you want to go bigger than those limits, you’ll need full planning permission instead. We check your Permitted Development eligibility for free, before any design work starts, no matter which of Surrey’s 11 councils you’re in.

Depends on your plot, but the usual options are a single-storey rear extension, a side extension, a wraparound, or a two-storey addition. Rear extensions are the go-to for extra kitchen or living space. Side extensions suit detached and semi-detached homes with room down the side. Two-storey works best if you’ve got a bigger plot and need more than one extra room. We’ll survey your property and tell you straight which option actually makes sense — and whether it’s PD-eligible — before you spend anything on design.

Around 8 weeks for a standard householder application, across all of Surrey’s councils. If you’re on Green Belt or AONB land, add a bit more time — up to 13 weeks, since it needs extra consultation. Once you’ve got permission, it’s valid for 3 years. A well-prepared application (which is what we submit for every client) cuts down the back-and-forth that usually causes delays.

Three main routes: a rear dormer (the most popular — full headroom, proper extra space), a Velux or rooflight conversion (no structural change outside, often falls under PD), or a hip-to-gable conversion, which works for detached and semi-detached homes with a hipped roof. If you’re in the Green Belt or an AONB, you’ll need full planning regardless of type. And whichever route you take, Building Regs Parts B, K and L still apply — fire safety, stairs, and energy efficiency.

A few things worth checking: are they RIBA chartered and ARB registered (the two qualifications that actually matter for UK architects), do they know your specific council, and do they have their own structural engineer in-house rather than outsourcing it. A solid track record with Green Belt or AONB approvals is a good sign too, since those areas are where planning gets strict. We tick all of these — RIBA-chartered, ARB-registered, working across all 11 Surrey councils since 2008, with an in-house structural engineer on every job.

Roughly £1,800–£2,500 per m² for a single-storey rear extension, so a 20m² extension usually lands somewhere between £36,000 and £50,000 before fit-out. Two-storey extensions cost more, since there’s extra structural work involved. The real number depends on your finish level, site access, and how complex the structure is — which is exactly what our free feasibility assessment is for, so you get a realistic figure before paying for design.

You’ve got two options: appeal to the Planning Inspectorate within 12 weeks, or resubmit a revised design within 12 months, usually without another planning fee. Most refusals come down to things like overlooking, scale, or a design that doesn’t sit well with the local area — all things we deal with at the design stage to keep approvals high. Our current approval rate across Surrey is 98%.

Quite possibly — big parts of Surrey sit within Green Belt or AONB land, including areas around Elmbridge, Guildford, Mole Valley, Waverley and Tandridge. In those areas, Permitted Development rights are usually removed, so most extensions need full planning permission. That doesn’t mean you’ll get refused — it just means the design has to show it won’t harm the openness of the land or the character of the landscape. We check your property’s designation as part of every free assessment.

Yes, but there’s an extra layer. Listed buildings need Listed Building Consent alongside (or sometimes instead of) standard planning permission, and homes in conservation areas usually lose some of their Permitted Development rights — so more types of extension need a full application. Materials and proportions get looked at more closely too, since the aim is to keep the property or the area’s character intact. We’ve secured approvals in Surrey’s conservation areas and on listed buildings before, so we know what these applications need to include.

Extension Architecture has extensive experience with 11 Surrey Councils — including Green Belt + AONB applications across GU1–TW20. RIBA-chartered, ARB-registered, in-house structural engineer, 98% planning approval rate. Free feasibility assessment for every Surrey enquiry before any design fee.

Architects in Surrey for House Extensions & Planning Applications