House Extension Services in Marylebone

Professional House Extension Solutions for Marylebone Residents

Free Site Visit

Fast Turnaround

Local Marylebone Expertise

High Planning Approval Rate

Professional House Extensions in Marylebone

Transform your Marylebone home with our professional house extension services. Our qualified architects combine local knowledge with innovative design to create extensions that perfectly complement your existing property while maximizing space and value. Whether you're planning a rear extension, side extension, or loft conversion, our Marylebone team delivers exceptional results that exceed expectations.

A recent extension project in the Westminster area

Local Expertise

Our Marylebone expertise is built on years of successful project delivery across the Enfield catchment area. We understand the local context, from conservation considerations to development opportunities, helping you make informed decisions about your house extension project. Our established relationships with local authorities and contractors ensure smooth project progression from initial design through to completion.

Planning & Regulations

Understanding Marylebone's planning policies and building regulations is crucial for successful project delivery. Our team has extensive experience working with Enfield Council and building control departments, ensuring your project meets all regulatory requirements. We stay current with changes to planning policy and building regulations affecting Marylebone, including updates to permitted development rights, conservation area guidelines, and sustainability requirements.

Property Types We Work With in Marylebone

Marylebone has a diverse housing stock and we have experience extending all property types in the area. Our architects adapt designs to suit the character and structure of each home, whether that means matching original brickwork on a period property or creating a contemporary contrast on a more modern home.

Victorian terraces

Edwardian semis

post-war council houses

1930s semis

modern townhouses

period conversions

Free Quote for Marylebone

Tell us about your project and get expert advice within 24 hours.

Get a Free Quote Call 020 3051 9430

Mon–Fri: 9am–5pm

Free site visit & consultation

No obligation quote

Covering W1 & surrounding postcodes

House Extension Costs in Marylebone (2026)

Guide prices for house extensions in the Westminster area. Every project is different — we provide a detailed, itemised quote after a free site visit.

Extension Type	Typical Cost	Build Time	Planning
Single Storey Rear Extension	£35k – £70k	3–4 months	Usually PD
Double Storey Extension	£55k – £120k	5–7 months	Full application
Side Return Extension	£25k – £50k	2–3 months	Usually PD
Wrap-Around Extension	£60k – £130k	4–6 months	Full application
Loft Conversion (Dormer)	£40k – £65k	6–8 weeks	Usually PD
Kitchen Extension	£30k – £60k	3–4 months	Usually PD
Basement Conversion	£80k – £200k	4–8 months	Full application
Garage Conversion	£15k – £30k	4–6 weeks	Usually PD

Prices are guide figures for 2026 based on projects in the Greater London area. PD = Permitted Development (no formal planning application needed in most cases). Actual costs depend on specification, site conditions, and scope.

Our Extension Services in Marylebone

Single Storey Extensions

Professional single storey extension design and planning for ground floor expansions

Typical: 6-12 weeks

Double Storey Extensions

Two-storey home extension design maximizing space and value

Typical: 8-16 weeks

Rear Extensions

Garden-facing extensions creating seamless indoor-outdoor living

Typical: 6-10 weeks

Side Extensions

Narrow extensions utilizing side garden space efficiently

Typical: 6-12 weeks

Kitchen Extensions

Specialized kitchen and dining space extensions for modern living

Typical: 8-14 weeks

Loft Conversions

Converting attic space into valuable living areas

Typical: 6-10 weeks

Basement Extensions

Underground extensions creating additional living space

Typical: 12-20 weeks

Planning Permission Services

Expert guidance through planning applications and permitted development

Typical: 8-16 weeks

Wrap Around Extensions

Comprehensive extensions combining rear and side elements for maximum space

Typical: 10-18 weeks

House Refurbishments

Comprehensive whole-house renovation and modernization services

Typical: 12-24 weeks

Structural Alterations

Expert structural engineering services including underpinning and load-bearing work

Typical: 8-16 weeks

Garage Conversions

Converting garages into functional living spaces for bedrooms, offices, and studios

Typical: 4-8 weeks

How Your Marylebone Extension Project Works

From the first phone call to moving into your new space — here is what to expect at every stage.

Step 1

Free Consultation

We visit your Marylebone property, discuss your vision, assess feasibility, and give you honest guidance on costs and planning routes.

Step 2

Design & Drawings

Our architects create detailed plans, 3D visuals, and construction drawings tailored to your Marylebone home and how you want to live in it.

Step 3

Planning & Approvals

We prepare and submit your planning application, liaise with the local authority covering Marylebone, and handle building regulations documentation.

Step 4

Construction

Our vetted builders bring the design to life. We oversee the build, conduct regular site visits, and manage quality at every stage.

Step 5

Completion & Sign-Off

Final inspections, building control sign-off, snagging checks, and handover — your new Marylebone space is ready to enjoy.

House Extension Services

Specializing in residential extensions across Marylebone, we provide tailored design solutions for every type of project. Our services include architectural design, planning applications, building regulations compliance, and construction drawings. We work closely with homeowners to create extensions that enhance their living space while maintaining the character and value of their property.

Planning Permission

Planning permission applications in Marylebone require careful preparation and local knowledge. Our team has successfully submitted numerous planning applications across the Enfield area, achieving high approval rates through thorough preparation and understanding of local planning policies. We handle all aspects of the planning process, from initial feasibility studies to final approval.

Completed house extension in Marylebone area

Extension completed in the Westminster area

Building Control

Our Marylebone building control services include detailed construction drawings, structural calculations, fire safety assessments, and accessibility compliance reviews. We understand the specific building control requirements for extensions in the Enfield area and can advise on structural solutions, thermal performance standards, and sustainability requirements.

Why Choose Us in Marylebone

Choosing the right architect for your Marylebone project is crucial for success. Our team offers a combination of professional expertise, local knowledge, and personal service that sets us apart from other architectural practices. We provide comprehensive extension services with a focus on quality, efficiency, and client satisfaction.

Helpful Guides for Your Marylebone Extension

Loft Conversions in London: The Complete 2026 Guide to Costs, Planning & Design

Everything you need to know about loft conversions in London in 2026. Dormer, hip-to-gable, mansard and L-shaped options explained with costs, timelines and planning permission guidance.

Kitchen Extensions in London: Ideas, Costs & Planning Permission Guide 2026

Plan your dream kitchen extension in London. Explore side-return, rear and wrap-around options with 2026 costs, planning tips and design inspiration for every budget.

House Extension Costs London 2026: Area-by-Area Price Guide

Updated 2026 price guide for house extensions across London. Costs for single storey, double storey, loft conversions and more — broken down by area and project type.

Frequently Asked Questions About House Extensions in Marylebone

How much does a house extension cost in Marylebone?+

House extension costs in Marylebone vary by type and size. Single storey rear extensions typically range from £35k – £70k, double storey extensions from £55k – £120k, and loft conversions from £40k – £65k. These are guide prices for 2026 — we provide an accurate, itemised quote after a free site visit to your Marylebone property.

Do I need planning permission for a house extension in Marylebone?+

Many extensions in Marylebone can be built under permitted development rights without a formal planning application. This typically covers single storey rear extensions up to certain size limits. However, if your property is in a conservation area, is a listed building, or if the extension exceeds permitted development limits, a full planning application is needed. During our free consultation we assess your Marylebone property and advise on the best route — and handle the entire application if needed.

What types of house extensions can you build in Marylebone?+

We design and build all types of extensions in Marylebone: single storey rear extensions, double storey extensions, side return extensions, wrap-around extensions, loft conversions (dormer, hip-to-gable, mansard), garage conversions, basement conversions, and kitchen extensions. Marylebone has a mix of Victorian terraces, Edwardian semis, post-war council houses — we tailor every design to the specific property type.

How long does a house extension take in Marylebone?+

Timelines vary by project: a single storey extension typically takes 3–4 months on site, a double storey 5–7 months, and a loft conversion 6–8 weeks. Before construction, the design and planning stage usually takes 8–12 weeks. We map out a detailed programme during your free consultation so you know exactly what to expect.

Do you handle planning applications with Marylebone council?+

Yes — we have extensive experience submitting planning applications to the local authority covering Marylebone. We prepare all drawings, design & access statements, and supporting documents, then manage communication with planning officers through to decision. Our knowledge of local policies helps avoid unnecessary delays or objections.

What areas near Marylebone do you cover?+

We cover Marylebone and all surrounding areas within a 20-mile radius. This means we can handle projects across the wider Westminster area, with the same level of local knowledge and expertise you'd get from a firm based in Marylebone itself.

Ready to Start Your Marylebone Extension?

Transform your Marylebone home with our professional extension services. Contact us today for a free consultation and discover how we can help you create the perfect extension for your property. Our experienced team combines local knowledge with innovative design to deliver exceptional results that enhance your home's value and living space.

Get a Free Quote Call 020 3051 9430