Home Extension Builders in Marylebone
Extension and reconfiguration in Marylebone W1U, where space is found inside the envelope and Buildaway engineers the openings that make it work.
Your Local Home Extension
Specialists in Marylebone
Looking for extension specialists in Marylebone (W1U)? Buildaway works throughout
Marylebone - the townhouses and flats off Marylebone High Street, Chiltern Street
and Manchester Square, and the buildings near Baker Street, Wigmore Hall, Harley
Street and Regent's Park.
Extension and reconfiguration in Marylebone is about finding space inside the
envelope, and Buildaway engineers the openings that make it work. W1U offers almost
no scope to build outward, so the gains come from removing structure, reworking a
plan and occasionally going down. Buildaway's Marylebone team confirms the listed
and freeholder position, designs the structure, then takes the job from feasibility
through to building control sign-off on one contract.
Our Home Extension Packages in Marylebone
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 Marylebone Homeowners Choose Buildaway
Local teams with expertise across Marylebone Village, W1, Baker Street, and West End neighbourhoods
Based in your area with local expertise and reputation.
Bespoke extension designs for Georgian homes, luxury apartments, and prime London residences
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.
Hassle-free project management ensuring seamless, high-quality results
Meticulous craftsmanship in every aspect of your extension.
Completed projects near Marylebone High Street, Regent's Park, and Chiltern Street
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 Marylebone 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.
“I am extremely impressed, happy and proud of what he and his team of Archie, Ben and Danny delivered. They all went beyond and far, I am very grateful for what they have done for me. I would 100% recommend Buildaway for any building, renovation etc - an excellent team with a good rapport, team spirit and working harmoniously together. Thank you Team Buildaway…”
Betty Lwanga
“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
“The quality of the work, their high standards, and their professionalism, along with effective and proactive communication made a refreshing change from the builders I have used in the past. Even when we changed our minds and ideas during the job Cormac’s patience and support emphasised that he wanted to make sure that the finished product was exactly what we wanted…”
Michael Marks
“From my first contact with Cormac, I was in good hands. His team turned my vision into reality, communicating with me every step of the way and offered helpful suggestions which turned my bathroom into an oasis. I could not be happier and would highly recommend their services. Thank you to the team of Buildaway Construction Ltd…”
Jackie Brown
“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
“We’ve had a genuinely fantastic experience with Buildaway. Cormac was ultra responsive and excellent at communicating with us throughout our project. The quality of the work was excellent - so much so, that we extended our project by adding a range of other building renovations to our original ask, each completed with care and precision…”
Kiran Collier
Frequently Asked Questions
Your questions about home extensions in Marylebone, answered.
How much does a home extension cost in Marylebone?
As a guide, a home extension in Marylebone (W1U) runs roughly £40,000–£60,000 for a single-storey rear, £60,000–£80,000 for a larger or wrap-around scheme, and £100,000+ for double-storey work. UK build costs sit around £1,800–£3,000 per m², and London consistently lands at the upper end. Buildaway fixes your figure in a written quote after survey.
How long does a home extension take in Marylebone?
Allow roughly 12–20 weeks of build in Marylebone, depending on scheme. The programme most people forget is before that: design, Westminster City Council approval and party-wall awards can add 3–4 months to a W1U project. Buildaway runs those in parallel and gives you a realistic combined timeline up front.
Do I need planning permission for an extension in Marylebone?
Many Marylebone single-storey rear extensions fall under permitted development, subject to depth, height and materials limits. But conservation-area designation around Marylebone High Street and Chiltern Street and listed status remove those rights, making Westminster City Council approval essential - and flats in W1U have no permitted development rights at all. Buildaway establishes your position before design.
What types of extension do you offer in Marylebone?
We handle single-storey, side-return, wrap-around, double-storey and basement extensions throughout Marylebone. The right answer for your W1U property depends on drainage, boundary and Westminster City Council policy. Buildaway establishes those before proposing anything.
Do Buildaway handle both design and construction for Marylebone extensions?
Yes. Buildaway takes Marylebone extensions from feasibility and design through Westminster City Council application, party-wall notices, Building Control, groundwork, structure and finish. One contract across every W1U project, so the design intent and the build are the same team's responsibility.
Are your extension specialists local to Marylebone?
We are in Marylebone constantly. Buildaway knows W1U property: the boundaries, the ground conditions, and how Westminster City Council treats rear additions here. That experience makes our feasibility advice reliable rather than optimistic.
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We Serve Marylebone and Surrounding Areas
Find us in the heart of Marylebone. 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 Marylebone?
Buildaway combines timeless design with expert craftsmanship - enhancing property value across Marylebone's exclusive market.