LOFT EXTENSIONS

House Extensions, Conversion & New Builds

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Our Services For Loft Conversion in London:

While loft conversions can dramatically increase living space and property value, they are far more complex than many homeowners first imagine. London boroughs often have tight planning controls, especially in conservation areas or for listed properties, while many London homes, particularly older Victorian and Edwardian terraces, require significant structural reinforcement to support the extra weight of a loft conversion. Therefore, engaging specialists can help homeowners navigate complex regulations and overcome structural challenges to ensure a smooth transformation.

Born and bred in London, we at Extension Architecture are a design and build architectural practice, with nearly two decades of expertise & specialisation in loft conversions & extensions. Our extensive experience in loft conversions, particularly across London, gives us the edge when it comes to handling projects regardless of scale and type. From compact Victorian terraces to spacious modern townhouses, we go all out in exhausting possibilities to create designs that manifest as airy and energy-efficient, comfy spaces. From staircase design to layouts that fit beautifully with the rest of the home, and managing builders and timelines, we are seasoned specialists who can add both charm and value to your loft space.

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Our Loft Extension Projects

Hammersmith & Fulham
Loft Conversion

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Clapham Loft
Conversion

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Park Road
Loft Conversion

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hosue extension

Surrey New Build
Loft Conversion

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What our Clients are Saying

Here's what some of our clients have to say about working with us, their stories reflect the trust, value, and impact we strive to deliver in every project.

Our process of building a
Loft Extension

Extension Architecture follows a structured, design-and-build process to ensure every loft conversion is delivered smoothly, on time and to the highest standard. Our approach covers every stage of the project, starting with feasibility studies to assess structural integrity, headroom, and design potential, along with ensuring compliance with full planning requirements. This is followed by integrating structural engineering expertise, including roof modifications, floor reinforcement, and staircase design, which guarantees both safety and longevity.

With end-to-end project management, Extension Architecture’s design-and-build approach takes the stress off your shoulders by coordinating contractors, managing timelines, and overseeing quality control, delivering loft conversions that are both aesthetically pleasing and highly functional.

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Types Of Loft Extensions

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Dormer Loft
Conversions

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Dormer Loft
Conversions

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One of the most popular options, dormer conversions extend vertically from the existing roofline to create extra floor space and headroom. They’re ideal for adding a spacious bedroom, home office, or en-suite bathroom while bringing in plenty of natural light through large windows.

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Hip to Gable Loft
Conversions

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extension

Best suited to properties with a hipped roof (sloping on all sides), this type extends the sloping side to create a vertical gable wall. It significantly increases the internal space, making it ideal for adding extra bedrooms or larger living areas.

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Mansard Loft
Conversions

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extension

Often chosen for properties in urban areas, a mansard conversion alters the roof’s pitch to create a near-vertical wall and flat roof. This design maximises headroom and can almost feel like adding a whole new floor to the property, perfect for high-end master suites or multiple rooms.

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L-Shaped Loft
Conversions

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L-Shaped Loft
Conversions

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An excellent option for period properties with an existing rear extension, L-shaped conversions combine two dormers to create an “L” shaped space. This layout is particularly effective for creating multiple rooms, such as a bedroom and a separate bathroom.

Other Services We Provide

Loft Conversions

Dormer Loft Extension

Our expertise in dormer loft conversions lies in delivering structurally refined, design-led solutions that maximise headroom, natural light, and spatial efficiency. We specialise in precision-engineered dormer designs that integrate seamlessly with existing rooflines while ensuring full compliance with planning and building regulations. From feasibility and technical drawings to construction, we create high-performance conversions that elevate comfort and property value.

Loft Conversions

Mansard Loft Extension

With mansard lofts, we create architecturally precise designs that optimise roof spaces into elegant, fully functional living areas. We specialise in achieving maximum headroom and natural light while maintaining structural integrity and aesthetic balance. Our expertise in detailed design, planning & construction, ensure a bespoke mansard conversion that enhance both value and livability.

Loft Conversions

Hip to Gable Loft Extension

Our expertise in hip-to-gable loft conversions lies in transforming underused loft spaces into expansive, structurally efficient living areas. With hip to gable conversions, we specialise in extending the sloping roof to a vertical gable wall, maximising internal headroom and floor area while maintaining architectural cohesion thus delivering high-performance conversions that enhance comfort, usability, and property value.

Any Questions?

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

Standard loft conversions in London tend to cost £50,000 to £90,000, depending on size, type, and finish. In the UK, it may cost £1,500 to £2,500 per square metre.
In most cases, you don’t need full planning permission for a loft conversion in London if the work falls under permitted development rights. For example, you can add a simple dormer or rooflight up to 40 m³ for terraced houses or 50 m³ for detached and semi-detached houses without altering the roofline facing the road without planning permission.  However, you will need planning permission if you live in a conservation area, plan major roof changes (like a mansard), or exceed the permitted development limits. Building Regulations approval is always required to ensure the conversion is safe and structurally sound.
It depends on the size, type, design, and regulatory requirements. In general, a loft conversion in London takes around 6-10 weeks for the construction work alone, with simpler versions (like roof windows / Velux) toward the shorter end.
Absolutely. A well-planned loft conversion is one of the most effective ways to increase a property’s market value, which may increase by 15–20%. This can be even higher in areas like London.
Not every home is suitable for a loft conversion. Factors such as the roof’s height and pitch (usually above 30 degrees), the structural strength of the existing building, ownership of the loft, and any planning restrictions, especially for properties in conservation areas or listed buildings, determine whether a conversion is possible.

Nikki

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