House Extensions, London
Premium Residential Extension Specialists
Premium Residential Extension Specialists
A thoughtfully designed house extension can transform the way you use and enjoy your London home – creating the additional space you need, enhancing the architecture and increasing the value of your property.
Whether you are looking to extend at ground-floor level to create a larger kitchen and living space, add a side-return extension or build a multi-storey extension to increase your accommodation, Advantage Basements & Renovations has the design and construction expertise to deliver.
Our integrated architectural and construction service manages every aspect of your extension – from the initial design concept and planning application through to construction and interior fit-out – ensuring a seamless, high-quality result from a single accountable team.
Single and Multi-Storey House Extensions in London
Single-storey rear extensions are the most common form of house extension in London, typically creating larger open-plan kitchen and dining or family room spaces that connect to the garden. Our architects design extensions that respond thoughtfully to the existing property and its context, maximising the space created and producing a design that complements the existing property.
Multi-storey extensions offer the opportunity to add accommodation at both ground and upper floor levels – creating additional bedrooms, bathrooms or studies alongside the enlarged ground floor living space. Our structural and planning expertise ensures that more complex multi-storey extensions are effectively designed and approved.
Building Works
Side Return and Wraparound Home Extensions in London
For terraced and semi-detached London properties, side return extensions utilise the narrow passageway alongside the house to extend the kitchen or living space laterally.
Side return extensions can be combined with a rear extension to create a wraparound scheme that transforms the ground floor, producing a large, open and light-filled space.
We have extensive experience delivering side return and wraparound extensions across London's terraced housing stock, and understand the planning, structural and party wall considerations specific to these project types.
Extend Your London Property with a House Extension
Contact Advantage Basements & Renovations to discuss a house extension for your property. Our team will advise on the design possibilities, planning prospects and costs specific to your home.
FAQs
How much does a house extension cost in London?
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House extension costs vary considerably depending on size, specification and complexity. As a general guide, modest single-storey rear extensions in London typically cost £2,000–£3,000 per square metre of floor area created for a mid-specification finish, rising to £3,500–£5,000 or more per square metre for high-specification builds with premium finishes and materials.
Larger extensions benefit from some economies of scale. Multi-storey extensions typically cost more per square metre than single-storey projects due to additional structural complexity. These figures include all construction costs and professional fees, but exclude VAT and certain contingency allowances.
Our project managers provide detailed cost estimates based on your specific brief following initial design work, ensuring you have clarity on the investment required before committing to the project.
Can I extend a London house right up to the boundary?
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Whether you can build right to the boundary depends on several factors. Planning policy varies between boroughs – some allow boundary extensions subject to design criteria, others maintain minimum separation distances.
Party wall considerations apply where construction is within three metres of a boundary and building up to the boundary typically requires party wall agreements with the adjoining owner.
Building Regulations require safe access for maintenance of the external face of the extension. Practical construction considerations, such as access for building and the excavation of foundations close to the boundary, must also be addressed.
Our architects and planning specialists advise on the specific constraints affecting your property, and our party wall team manages any necessary agreements with neighbours.
Will my house extension affect natural light to neighbouring properties?
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Extensions can potentially affect natural light to neighbouring properties, and this is a key consideration in planning assessments. Local planning authorities use technical tests to assess whether an extension would cause unacceptable loss of light to neighbours.
The 45-degree rule uses an imaginary 45-degree line drawn from a neighbouring window to assess whether an extension could cause an unacceptable loss of light.
The BRE daylight and sunlight guidance measures how a proposed development may affect daylight, sunlight and overshadowing to neighbouring properties.
Our architects design extensions with these considerations in mind, positioning and sizing new structures to minimise impact and maximise the accommodation. When planning concerns about neighbour amenity are anticipated, we prepare detailed daylight and sunlight assessments as part of the planning application to demonstrate that impacts are within acceptable limits.