Do I need an architect for a house extension in London?

While it's not a legal requirement, working with a qualified architectural designer ensures your project meets building regulations, maximises your planning approval chances, and avoids costly mistakes.

How much does it cost to hire an architect in London?

A simple rear extension design starts from £800 + VAT. Double storey extensions from £1,000 + VAT. Loft conversions from £800 + VAT. Salstan offers free consultations and fixed-fee quotes.

How long does the architectural design process take?

A typical residential project takes around 4 weeks from initial consultation to planning submission. Planning decisions usually take 8 weeks for householder applications. Technical drawings take an additional 5-7 working days after planning approval.

Do you offer a design and build service?

Yes. Salstan is a full-service, turnkey practice. We manage projects from initial concept through to completed construction, including architecture, structural engineering, and building works - all under one roof.

What areas of London do you cover?

We cover all 33 London boroughs from our offices in Park Royal and Teddington. We also work across Hertfordshire, Surrey, Essex, Kent, and other Home Counties.

Can you help if my planning application has been refused?

Yes. We regularly help clients who have received planning refusals. We review the council's reasons for refusal, redesign the scheme to address their concerns, and resubmit or lodge a formal planning appeal where appropriate.

House Extension

More room, No Fuss

Experience straight forward house extensions in London with our expert touch.

Explore the Right Extension Type for Your Home

Extension Types

Rear Extensions

Open-plan kitchen-diners, garden rooms and ground-floor living spaces designed around your lifestyle.

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Kitchen Extensions

Transform your kitchen into a bright, open-plan space perfect for cooking, dining and family living.

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Wraparound Extensions

Rear and side combined for maximum internal space — ideal for open-plan kitchens and family rooms.

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Double Storey Extensions

Two-floor extensions for growing families — maximising space from your available footprint.

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Basement Conversions

Unlock hidden space beneath your home — create cinema rooms, gyms, offices or extra bedrooms below ground.

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Loft Conversions

Dormers, hip-to-gables and roof extensions — adding bedrooms, offices and bathrooms upstairs.

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What is a House Extension?

Planning house extensions in London? A house extension adds new space to your existing home — whether it’s a bigger kitchen, an extra bedroom, or even a home office. At Salstan, we make it straightforward to get more room without moving. Furthermore, it pays off. A well-designed extension can increase your property’s value by up to 20%.

Our House Extension Services in London

Our Portfolio

Rainham, London

Rear Extension

Single-storey rear extension with bi-fold doors and contemporary kitchen design.

Gerrards Cross

Rear Extension

Elegant rear extensions with big bifold doors, apex windows and skylights, flooding the space with maximum natural light.

Ilford, London

rear Extension

Modern rear wraparound extension to a victorian property creating seamless indoor-outdoor living with floor-to-ceiling glazing.

Croydon, London

Wraparound Extension

L-shaped wraparound extension maximising ground floor living and dining space. On this project we actually completed the loft dormer extension, double storey side and partial first floor rear extensions too!

Kensal Rise, London

Wraparound Extension

Side and rear wraparound extension with modern kitchen and open-plan family area. Featuring big crittal doors and large skylights on the sloping roof.

Wandsworth, London

Wraparound Extension

Full wraparound extension with panoramic glazing and premium specification. Can you spot the overall balance with the L-shape loft dormer extension we also designed for this client?

Bromley, London

Double Storey Extension

Two-storey side extension with matching brickwork, extra bedrooms and bathrooms. In fact we also re-designed the entire loft space and had major approvals for an approx 6m by 14m ground floor wraparound extension!

Windsor

Double Storey Extension

Grand double-storey rear extension with integrated garage and a full internal remodel of the entire home.

Richmond, London

DOUBLE STOREY EXTENSION

Grand double storey rear extension with open-plan kitchen-diner and master suite above.

Merton, London

Loft Conversion

Hip-to-gable dormer loft conversion/extension to accomodate a master suite with a walk-in wardrobe and a modern ensuite.

Purley, London

Loft Conversion

Front cottage dormers and a large rear box dormer extension/conversion with Juliet balcony and vaulted ceiling bedrooms. This was pure luxury.

Thames Ditton, Surrey

Loft Conversion

Hip-to-gable loft dormer conversion/extension with premium finish. We had to design something different as opposed to the standard dormer extension so it can blend in with the rest of the extensions we designed for this house.

East London

Flat Conversion

Victorian end of terrace mixed use properties converted into a luxury two-bedroom flats with modern amenities.

Crystal Palace, London

Flat Conversion

Property subdivisions into modern self-contained apartments.

Barnet, London

Flat Conversion

Full house-to-flats conversion with multiple large extensions and comprehensive planning and building regulations approval.

Wembley, London

New Build

Contemporary new-build family homes with open-plan living and sustainable design features.

Surrey

New Build

Bespoke new-build bungalow development designed from foundation to completion.

Harrow, London

New Build

Multi-unit new-build project with distinctive architectural detailing and landscaping.

Why Are We the Best for House Extensions in London?

Experienced Planning Experts

Over a thousand successful house extensions delivered in London — we understand what planning officers look for and design accordingly.

Expert In-House Team

Architectural designers, structural engineers, technicians and construction managers — all working together under one roof.

Fixed-Fee Pricing

Clear pricing from the start with no hidden costs or hourly surprises. You know exactly what you are paying before we begin.

On Time, On Budget

Projects completed within the timeframes and budgets agreed from the very first consultation — no overruns or surprises.

Clear Communication

A dedicated team keeps you updated at every stage — you always know exactly what is happening with your project.

Flexible Design Approach

Plans change — we adapt quickly and make sure the final result is exactly what you envisioned, even if the brief evolves.

Frequently Asked Questions

We offer everything from small house extensions in London to full wraparound and multi-storey extensions. Our architectural designers tailor each design to your property and needs.

Some house extensions fall under permitted development, but many require planning permission. We handle the full application process, including party wall agreements and local authority coordination.

Project timelines vary, but most house extensions in London are completed within a few months. Salstan ensures efficient progress without sacrificing quality.

Yes. Our holistic design approach means we plan for practicality and aesthetics — making sure your new space works hard for you.

We anticipate and manage these issues with professional diplomacy. From early discussions to final approvals, we ensure a smooth and compliant process for every house extension we deliver.