Two Storey Extensions in London
Doubling your space with two storey extensions that add bedrooms, bathrooms, and living space — the most cost-effective way to expand your home.
About This Service
Two Storey Extensions in London
A two storey extension is the most efficient way to add substantial space to your home. By extending across two floors, you gain additional bedrooms and bathrooms upstairs while creating a larger kitchen or living space downstairs — all for a lower cost per square metre than a single storey extension.
More Space has designed two storey extensions across London, from rear additions on Victorian terraces to side extensions on suburban semis. We understand the structural complexity, planning considerations, and neighbour implications that two storey projects involve, and we manage every aspect from concept to completion.
Two storey extensions require careful massing to protect neighbouring amenity and right to light. Our team has the expertise to design extensions that are ambitious yet sensitive — additions that give you the space you need while maintaining good relationships with your neighbours and securing planning approval.
Key Benefits
Advantages of a Two Storey Extension
Additional Bedrooms
Add master suites, children's bedrooms, or guest rooms to accommodate a growing family or create a home office.
En-Suite Bathrooms
Create a master suite with dressing room and en-suite, or add a family bathroom to ease morning routines.
Cost Efficiency
Two storey extensions cost less per square metre than single storey, as foundations and roof are shared across both floors.
Maximum Value
Adding bedrooms and bathrooms is one of the highest-value home improvements, particularly in family-friendly London areas.
How We Work
Our Two Storey Extension Process
Feasibility assessment covering structural implications, planning policy, and neighbour impact
Concept design exploring massing, roof form, and internal layout across both floors
Daylight and sunlight assessments to demonstrate neighbour impact is acceptable
Planning application with full design rationale and neighbour consultation
Construction including structural works, party wall management, and full fit-out
Recent Projects
Two Storey Extensions We've Delivered
Common Questions
Two Storey Extensions FAQs
How much does a two storey extension cost?
Two storey extensions in London typically cost £2,000–£3,500 per square metre, making them more cost-effective per m² than single storey extensions. A typical 40 m² two storey extension (20 m² per floor) costs between £100,000 and £180,000. We provide detailed estimates at the concept stage.
Do two storey extensions need planning permission?
Yes — two storey extensions almost always require full planning permission, as they exceed permitted development limits. They're also more likely to face scrutiny over neighbour amenity, particularly regarding overlooking and right to light. We manage the entire planning process, including pre-application advice where beneficial.
Will a two storey extension affect my neighbours' light?
Two storey extensions can affect neighbouring properties' daylight and sunlight, which is why we commission daylight assessments early in the design process. We design the massing and window positions to minimise impact, and we present the assessment results to planning officers to demonstrate that the effect is acceptable.
Can I live in my home during a two storey extension?
It's usually possible to remain in your home, though there will be periods of significant disruption, particularly during structural works and first-floor construction. We phase the works to maintain access to essential facilities and can advise on temporary arrangements for the most disruptive periods.
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 Two Storey Extensions Project
Book your initial consultation. We'll visit your property, discuss your vision, and provide a clear pathway to making your two storey extensions a reality.