Side Extensions in London
Unlocking the hidden potential of side returns and passages, transforming narrow spaces into light-filled living areas that maximise every inch of your property.
About This Service
Side Extensions in London
A side extension — often called a side return infill — is one of the most transformative projects you can undertake on a London terraced house. By extending into the narrow passage alongside your home, you can significantly increase your ground floor footprint, bring natural light deep into the plan, and create a spacious kitchen-diner that wasn't possible before.
More Space has completed side return infills across London, from Victorian terraces in Lambeth to Edwardian homes in Fulham. We specialise in glazed roofs that flood the space with daylight, open plan layouts that connect kitchen, dining, and living areas, and seamless transitions to the garden.
Side extensions require careful planning, particularly where they affect neighbouring properties' right to light. Our team has the expertise to navigate party wall agreements, daylight assessments, and conservation area constraints to deliver a side extension that's both ambitious and compliant.
Key Benefits
Benefits of a Side Extension
Maximise Space
A side return infill can add 10–15 m² of floor space to your ground floor, transforming a narrow passage into a usable living area.
Glazed Roofing
Frameless glass roofs and rooflights bring daylight into the deepest parts of your home, brightening previously dark interiors.
Open Plan Layouts
Remove walls between kitchen, dining, and reception rooms to create a flowing, sociable ground floor.
Garden Access
Reposition the garden access to the end of the new space, creating a direct connection from kitchen to garden.
How We Work
Our Side Extension Process
Site survey and feasibility assessment, including party wall implications and right-to-light analysis
Concept design exploring layout, glazing, and roof options for your side return
Party wall agreements and neighbour consultations managed on your behalf
Planning application or lawful development certificate as appropriate
Construction with structural works, glazing installation, and interior fit-out
Recent Projects
Side Extensions We've Delivered
Common Questions
Side Extensions FAQs
What is a side return infill?
A side return infill is an extension that fills in the narrow passage typically found alongside Victorian and Edwardian terraced houses. This passage is usually too narrow to be useful but, when infilled, adds significant usable space to the ground floor and allows for a glazed roof that brings in natural light.
Do I need my neighbour's permission for a side extension?
If the extension affects a shared wall or boundary, you'll need a party wall agreement with your neighbour. This is a legal requirement under the Party Wall etc. Act 1996. We manage this process for you, serving the correct notices and negotiating with your neighbour's surveyor if needed.
Can I have a glass roof on a side extension?
Yes — glazed roofs are one of the most popular features of side return infills. Frameless glass roofs, rooflights, and lantern lights all bring natural light into the space. We design the structural support to achieve minimal sightlines while meeting building regulations for thermal performance and drainage.
How much value does a side extension add?
A well-designed side return extension can add 10–20% to your property's value, particularly in London where space is at a premium. The combination of additional floor area, natural light, and modern open plan living makes it one of the highest-return home improvement projects.
Instant Estimate
Design & Drawings Cost Estimator
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Project Type
Approximate Size
25 m²Design & Drawings
Indicative design & drawings fee
This is an indicative guide based on typical London design fees. Your actual quote will depend on site conditions, planning requirements, and project scope.
Book a Consultation
Start Your Side Extensions Project
Book your initial consultation. We'll visit your property, discuss your vision, and provide a clear pathway to making your side extensions a reality.