DOMINANT CONSTRUCTION

Elegant, functional, and bespoke renovations

designed for modern living spaces.

Consultation

Why Choose Dominant Construction in Chelsea

Builders in Chelsea work within some of the tightest planning constraints in London — the majority of the area sits within a conservation area governed by the Royal Borough of Kensington and Chelsea (RBKC), and a significant number of properties carry listed status. We deliver home renovations, house extensions, loft conversions, and basement conversions across SW3 and SW10, with every project planned around RBKC's specific requirements from the outset rather than discovered partway through.

Our team works directly with RBKC's planning and conservation officers, meaning we can tell you what's realistic for your property before a design is drawn — not after a refusal. We're FMB-registered, use JCT contracts on every project, and manage the full process in-house: structural work, planning liaison, and finishing trades, under one team.
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CONCEPT TO COMPLETION

Our multi-faceted team offers a comprehensive range of specialist skills across the full spectrum of interiors, architecture and construction, resulting in an outstanding portfolio of projects.
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House Extensions in Chelsea

Chelsea's streets are lined with Victorian and Georgian terraces, and any extension here has to work with that character rather than against it — matching brickwork, window proportions, and roofline to the existing property, particularly on anything visible from the street. Beyond the conservation area rules, an extension is usually the more sensible financial move over moving house entirely: stamp duty and agent fees on a Chelsea property routinely run into six figures, making a well-designed extension the better investment in most cases.

Popular Types of House Extensions

Rear extensions — the most common approach in Chelsea, typically extending the kitchen or living space into the garden. Often combined with bifold or crittall-style glazing to bring in natural light while keeping the front elevation untouched.

Side return extensions — infilling the side alley space common on Victorian terraces, usually to widen a kitchen-diner. A cost-effective way to add meaningful space without a full rear extension.

Double-storey extensions — extending at both ground and first floor, typically used to add an extra bedroom or bathroom above an extended kitchen below. More involved structurally, and more likely to require full planning permission given the additional roofline impact.

What Determines Extension Cost in Chelsea

Several factors set the final cost of a house extension in Chelsea:


Size and layout — footprint, number of storeys, and structural complexity Type of extension — rear, side return, wraparound, or double-storey Materials and finishes — brick matching, glazing specification, roofing Planning requirements — full planning permission is the norm in Chelsea's conservation areas, adding both time and design cost Site access — narrow terraced streets often mean higher labour and logistics costs than outer London.


Rear extensions in Chelsea typically run £80,000 to £200,000; side return conversions from £50,000 to £100,000; double-storey extensions £150,000 to £300,000, depending on specification.


Contact us today to discuss your house extension project in Chelsea and get a free no obligation quote. Our team is ready to provide you with expert advice and tailored solutions. Let us help you create a space that meets your needs and exceeds your expectations.

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Loft Conversions in Chelsea

We are local builders specialising in home renovation and refurbishment, house extension, loft or basement conversions.
Whether you are looking to expand the footprint of your Chelsea property, increase the usable space within the existing structure or increase your property’s rental or sales value by updating it, we are here to help.
As local builders in Chelsea, we understand the nuances of the area, architecture and any restrictions. So get in touch with our team of Chelsea builders today to explore your house build. Our team of project managers are ready to discuss how we can help you achieve your vision.

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Loft Conversion Types and Costs

Conversion type

What it involves

Typical cost

Roof light (Velux)

Skylight windows added to the existing roof, no structural change

£25,000 – £50,000

Dormer

Box-shaped extension to the rear roof slope, adds standing height

£45,000 – £70,000

Hip-to-gable

Converts a sloping hip roof into a vertical gable wall, common on semi-detached properties

£45,000 – £70,000

Mansard

Replaces most of the roof slope with a near-vertical wall, maximises space

£60,000 – £100,000

L-shaped dormer

Combines a rear dormer with a side extension over the back addition

£50,000 – £80,000


Several factors move these figures: the loft's existing size and structural condition, the complexity of the chosen design, materials and finish specification, and whether Listed Building Consent applies in addition to standard planning permission. Consulting a builder with direct RBKC experience — rather than general London experience — gives a far more reliable estimate, since planning risk in Chelsea specifically has a bigger impact on both cost and timeline than in less protected boroughs.

For a free consultation on your loft conversion in Chelsea, contact us.
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Basement Conversions in Chelsea

Basement conversions turn underused cellar space into genuinely functional rooms — a home cinema, gym, or additional living space — without altering the external footprint of a property where extending outward isn't an option on most Chelsea terraces.
Because Chelsea sits almost entirely within RBKC's conservation areas, and many properties carry listed status, basement work involves considerably more than excavation. We manage structural engineering, party wall agreements with neighbouring properties, and RBKC's planning process end-to-end.
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What Determines Basement Conversion Cost

Project type

Description

Typical cost

Basic conversion

Existing basement converted to a habitable room, no excavation

£100,000 – £200,000

Full excavation

No existing basement, or excavation needed to increase ceiling height

£250,000 – £500,000

Double-level basement

Extensive excavation and underpinning for maximum added space

£500,000+


Cost is driven primarily by excavation depth and underpinning method, waterproofing system (typically Type C cavity drain tanking to BS 8102), ventilation and lighting solutions, structural complexity including party wall agreements, and finishes specification.

For a precise estimate based on your property, contact us for a free consultation. We'll assess your specific structure and listing status before giving you a number.
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LOFT CONVERSIONS IN CHELSEA

A Creating more space at home is becoming an essential step for many homeowners, particularly in sought-after areas like Chelsea. With property prices skyrocketing, transforming the underutilised loft in a home is often the best way to add functionality and value without the hassle of moving. Loft conversions are becoming a popular solution, offering endless possibilities to enhance living spaces. For those looking to maximise potential, Dominant Construction stands out as a trusted partner for loft conversions in Chelsea. A loft conversion is more than just adding an extra room—it’s about improving your living experience. Chelsea's mix of stunning Victorian, Georgian, and Edwardian architecture makes loft conversions an appealing option for homeowners. They offer the chance to maintain the charm of period properties while modernising interiors to suit today’s lifestyle.
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AVERAGE LOFT CONVERSION PRICE IN CHELSEA

Below is an overview of the average costs for different types of basement conversions (sourced from across London, for reference only):

Name

Description
Average Cost
Velux/Rooflight Price Price

The most affordable option, a Velux conversion, adds skylight windows to your existing roof without major structural changes.

£25,000 to £50,000
Dormer Price

This option transforms a sloping “hip” roof into a vertical “gable” wall, maximising space in semi-detached properties..

£45,000 to £70,000
Hip-to-Gable Price

A more complex project, a double-level basement adds significant space to your property but requires extensive excavation, underpinning, and design expertise.

£45,000 to £70,000
Mansard Price

Ideal for period properties or those in conservation areas, a Mansard conversion significantly alters the roof’s structure to add the most space.

£60,000 to £100,000
L-Shaped Dormer Price

Perfect for Victorian or period properties, this extension maximises space by extending both the rear and side roofs.

£50,000 to £80,000

Factors Influencing Loft Conversion Costs

Several elements can impact the overall price of a loft conversion, including:

  • The size and structure of the loft
  • The complexity of the design
  • The type of materials chosen
  • Planning permissions and building regulation compliance
  • Additional features like en suite bathrooms or bespoke cabinetry
Consulting with an experienced local builder such as Dominant Construction in Chelsea can provide a more accurate estimate and help ensure that the loft conversion meets all necessary standards, thereby enhancing the property’s value.

Contact us now for a free consultation to discuss your loft conversion project in Chelsea.

START YOUR CHELSEA PROJECT

If you're planning a renovation, extension, or conversion in Chelsea, get in touch for a free consultation. We'll assess your property, talk through what's realistic given RBKC's requirements, and give you a clear, honest scope before anything is agreed.

Call 020 7118 6155, visit us at 185 Fulham Palace Road, W6 8QX, or see recent projects at dominantconstruction.co.uk.
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