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Flat Conversions 
In London

Maximising the potential of your property through efficient layouts, planning expertise, and a fully managed conversion process from feasibility to construction.

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Developers
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Professional Flat Conversion Architects in London

Flat conversions are an excellent way to maximise the value and potential of an existing property. Whether converting a large house into multiple self-contained flats or transforming unused space into a functional apartment, a well-designed conversion can significantly increase both rental yield and property value.


At Extension Architecture, we work closely...

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Extension Architecture’s Gallery

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Our Flat Conversion 
 Architecture Services

At Extension Architecture, we manage flat conversion projects from feasibility to construction, assessing buildings, planning policies, and layouts to create compliant, well-planned residential spaces.

Comprehensive 
Service

A comprehensive architectural service for flat conversion projects, guiding clients from the initial feasibility stage through to construction.

Reason ↗ (1)

Design & Planning Management

Managing the design, planning applications, and technical documentation required to successfully convert a property into multiple residential units.

Reason ↗ (2)

Maximising Layout Potential

Carefully assessing the existing building, local planning policies, and layout possibilities to maximise viable flats while maintaining good living standards.

Reason ↗ (3)

Coordinated Delivery

Coordinating design, planning approvals, and technical drawings to ensure the project progresses smoothly while protecting architectural quality and long-term value.

Reason ↗ (4)

Our Featured Flat Conversion Projects

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Gypsy Flat Conversion

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Gypsy Flat Conversion

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Gypsy Flat Conversion

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Wraparound extension at 82 Norfolk Road, Streatham

Gypsy Flat Conversion

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Our Process for Designing 
and Delivering a Flat Conversion

At Extension Architecture, we take immense pride in offering comprehensive services that cater to the unique needs of each new build project. Our team of new build and custom home architects are adept at blending creativity with technical expertise to bring your ideas to life. By choosing our services, you benefit from:

View Full Process
01

Initial Consultation & Feasibility

Every project begins with a detailed consultation to understand your goals and assess whether the building is suitable for conversion. We review the existing layout, site constraints, and local planning policies to determine the most effective approach.

02

Layout Design 
& Space Planning

We develop carefully considered layout proposals that divide the property into well-designed, self-contained flats, prioritising efficient space planning, natural light, and compliance with housing standards.

03

Planning 
& Approval

We prepare planning drawings and documentation, manage the submission to the local authority, and respond to any queries throughout the planning approval process.

04

Planning 
& Approval

We prepare planning drawings and documentation, manage the submission to the local authority, and respond to any queries throughout the planning approval process.

Start Planning a New Build Home

If you are planning a new build home in London, our architects can guide you through the entire process from concept design to construction.

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Architectural design consultation and home extension planning services Architectural design consultation and home extension planning services Architectural design consultation and home extension planning services
Years of Experience

17

Other Services
that we Offer

Check out our other services that we offer for new build

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At Extension Architecture:

we take immense pride in offering comprehensive services that cater to the unique needs of each new build project. Our team of new build and custom home architects are adept at blending creativity with technical expertise to bring your ideas to life. By choosing our services, you benefit from:

08 22Fa

At Extension Architecture:

we take immense pride in offering comprehensive services that cater to the unique needs of each new build project. Our team of new build and custom home architects are adept at blending creativity with technical expertise to bring your ideas to life. By choosing our services, you benefit from:

08 22Fa

At Extension Architecture:

we take immense pride in offering comprehensive services that cater to the unique needs of each new build project. Our team of new build and custom home architects are adept at blending creativity with technical expertise to bring your ideas to life. By choosing our services, you benefit from:

08 22Fa

At Extension Architecture:

we take immense pride in offering comprehensive services that cater to the unique needs of each new build project. Our team of new build and custom home architects are adept at blending creativity with technical expertise to bring your ideas to life. By choosing our services, you benefit from:

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Any Questions?

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

A Green Belt architect combines design expertise with specialist knowledge of Green Belt planning policy. At Extension Architecture, the architectural work and the planning strategy are developed together from the outset, not treated as separate workstreams. We understand what constitutes inappropriate development, when exceptions apply, and how to structure an application and its supporting evidence to give it the strongest possible prospect of success.
Yes, but the range of acceptable development is more limited than in non-designated areas, and the planning process demands more careful management. Extensions to existing dwellings, barn conversions, replacement dwellings, and certain community uses can all be acceptable subject to policy criteria. New standalone residential development generally requires a clear and evidenced Very Special Circumstances case. We assess each site on its own merits and give you an honest view of what is realistically achievable.
In most cases, yes. The Green Belt designation means that a wider range of works require a formal planning application than would be the case on a standard residential plot. Works that fall within Permitted Development elsewhere can require Prior Approval, or be restricted entirely, in the Green Belt. We confirm the correct planning route for your specific project as part of our initial feasibility assessment, before you commit to anything
Fees depend on the complexity, scale, and planning risk profile of the project. Green Belt work typically requires more upfront planning strategy, additional supporting documents such as planning statements and heritage assessments, and greater engagement with the Local Planning Authority than a standard application. We provide a transparent, project-specific fee proposal after an initial consultation. We are happy to discuss the likely fee range at the outset so there are no surprises.
The NPPF sets out the uses that are not considered inappropriate in the Green Belt: extensions to existing buildings, replacement dwellings subject to scale criteria, barn and agricultural conversions, outdoor sport and recreation, limited infilling within villages, and community or institutional development. New standalone residential development requires Very Special Circumstances to be clearly demonstrated. We assess your site and project against current national and local policy to identify the strongest available planning route.
Longer than a standard application, in most cases. A Local Planning Authority has 8 weeks to determine a householder application and 13 weeks for a major application, but complex Green Belt cases frequently require pre-application engagement, additional consultation rounds, or referral to planning committee, all of which extend the programme. We set realistic timescales from the start, manage the process proactively, and keep you informed at every stage.
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