Home Extension Builders in Belgravia
Extension and lower-ground works for Belgravia SW1X and SW1W, delivered by Buildaway with the structural care and consent handling that listed property demands.
Your Local Home Extension
Specialists in Belgravia
Searching for extension specialists in Belgravia (SW1X, SW1W)? Buildaway works
throughout SW1 - the townhouses of Eaton Square, Belgrave Square and Wilton
Crescent, the mews properties off Elizabeth Street and Motcomb Street, and the homes
toward Chester Square, Knightsbridge and the Pimlico Road.
Extension and lower-ground works for Belgravia are delivered by Buildaway with the
structural care and consent handling that listed property demands. In SW1X and SW1W
the space is almost always won downward or inward, which makes underpinning,
waterproofing and party-wall engineering the heart of the job. Buildaway secures the
consents, engineers the structure and runs the build discreetly - one accountable
Belgravia team, one programme, one fixed specification.
Our Home Extension Packages in Belgravia
Single-Storey Rear Extension
Ideal for expanding your living space. Includes structural survey, architectural drawings, groundworks and foundations, brickwork and roofing, bi-fold or sliding doors, heating installation, building regulation approval.
Side Return Extension (Most Popular)
Complete kitchen and living area transformation. Includes structural assessment, full groundworks, steelwork if required, brickwork and matching materials, glazing and doors, full insulation, electrics upgrade, flooring, building regulation approval, waste removal.
Double-Storey Extension
For those seeking maximum space addition. Includes architectural design, full structural alterations, steelwork and foundations, bespoke staircase, multiple room creation, bathroom or en-suite option, planning and building regulation handling.
Why Belgravia Homeowners Choose Buildaway
Flawless, luxury installations with minimal disruption
Based in your area with local expertise and reputation.
Bespoke extension designs for listed townhomes, mews properties, and apartments
We handle everything so you don't have to worry.
Transparent and honest pricing with no hidden fees or unexpected charges.
Clear upfront pricing with no surprises along the way.
Trusted by residents across Eaton Square, Chester Square, and surrounding areas
Meticulous craftsmanship in every aspect of your extension.
Full project management for a seamless, stress-free experience
Professional consultation and detailed quotes at no cost.
What's Included in Your Home Extensions Services
Everything you need for a seamless, stress-free home extension - from structure to finish.
Full groundworks and structural build
Complete groundwork preparation and structural construction services.
Plumbing, electrics, and heating integration
Professional installation of all mechanical and electrical systems.
Roofing, windows, and external finish
Complete roofing, window installation and exterior finishing.
Plastering, flooring, and decorating
Professional plastering, flooring and decorating services.
Interior fit-out and finishing
Complete interior fit-out and professional finishing touches.
Project management and schedule control
Professional project management and timeline control throughout.
Latest Home Extension Insights
We publish detailed home extension guides and cost insights for homeowners across Belgravia and surrounding areas, helping customers plan projects with clarity before starting work.
Home Extensions London: The Complete 2026 Guide
Everything from feasibility and planning to structure, cost and programme for a London extension.
Single-Storey Rear Extension Cost London
A realistic cost breakdown for the most common extension in London, with the variables that move it.
Planning Permission for Home Extensions
When you need permission, when permitted development covers you, and how to avoid a refusal.
What Our Clients Say
Real reviews from our satisfied customers.
“A great transformation of my bathroom into something modern and sleek. Cormac was professional to work with from the start and was very helpful in taking my ideas and sourcing products to fit the space and look aesthetically pleasing. I felt confident in working with the company as I could ask questions and I was also pleased to get suggestions and ideas…”
Vera Jajechnyk
“The team turned up when they said they would and kept the house tidy each day, which made a big difference while we were living in the property during the works. The quality of the finish is excellent. The bathroom looks fantastic and the bedrooms feel completely refreshed. We wouldn’t hesitate to recommend Cormac and the Buildaway team…”
Helen Sivyer
“I received an excellent service from the outset with a very high standard of the completed work. Cormac was very responsive to my wish for a traditional period bathroom and helped me to source the suite, the tiles, the paneling and flooring. The team are respectful to the home generally. I am very pleased with the finished bathroom…”
Philomena Mulcahy
“We had an excellent experience working with Buildaway. Cormac was incredibly easy to work with, and gave helpful advice. The finished job was neat, professional and completed efficiently. We'd definitely recommend and would use them again!”
Roisin Lawrence
“It was an absolute pleasure working with Cormac and the Buildaway team. Greg is an absolute star. Cormac’s communication and advice was excellent, and the organisation and sourcing of additional materials was brilliant. A truly great team, I would thoroughly recommend Buildaway if you are after a stress free and top quality renovation.”
Sim Lewis
“They were also very professional day to day - always tidy, and cleaned up really thoroughly when taking away all rubbish at the end. They stuck to the agreed timelines, and pricing was transparent throughout, with clear communication on any issues as they arose. Overall, I’m really pleased with the result and felt I could trust them throughout. I wouldn’t hesitate to recommend them…”
Sean Kelleher
Frequently Asked Questions
Your questions about home extensions in Belgravia, answered.
How much does a home extension cost in Belgravia?
Extension costs in Belgravia are driven by groundwork, structure and glazing more than floor area alone. Across SW1X and SW1W, expect about £40,000–£60,000 for a single-storey rear, £60,000–£80,000 for wrap-around, £100,000+ for double-storey. Buildaway itemises groundwork, steels, services and finishes separately so the trade-offs are visible.
How long does a home extension take in Belgravia?
Twelve to twenty weeks on site for Belgravia, scheme depending. The build is the predictable part; Westminster City Council determination and party-wall awards are what stretch SW1X and SW1W projects. Buildaway handles both alongside design so the dates hold.
Do I need planning permission for an extension in Belgravia?
Assume it may. Belgravia extensions frequently run into conservation-area policy or listed-building consent, and SW1X and SW1W flats cannot use permitted development regardless. Buildaway resolves the Westminster City Council position first, because it determines what is worth drawing.
What types of extension do you offer in Belgravia?
Rear, side-return, wrap-around, double-storey and lower-ground - Buildaway delivers all of them in Belgravia. Terraces around Eaton Square and Elizabeth Street usually point to a side-return; where outward space is limited in SW1X and SW1W, going down or reconfiguring inside often makes better sense. We advise from survey.
Do Buildaway handle both design and construction for Belgravia extensions?
Yes - design, planning and construction under one Buildaway contract in Belgravia. That single accountability is the main reason our SW1X and SW1W extensions finish on the dates we committed to.
Are your extension specialists local to Belgravia?
Yes, Belgravia is core Buildaway territory. We build extensions across SW1X and SW1W regularly and understand both the buildings and the Westminster City Council policies that govern them.
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We Serve Belgravia and Surrounding Areas
Find us in the heart of Belgravia. We are proud to serve our local community.
Nearby Areas We Serve
Below are some of the local areas where you can find Buildaway transforming homes.
Ready to Transform Your Extension in Belgravia?
We’ve worked within Belgravia’s most exclusive streets, understanding the expectations of privacy, quality, and precision required.