Add space across two floors with one coordinated design
Double-Storey House Extension North London
A double-storey extension can transform ground-floor living space while adding bedrooms, bathrooms or a home office above. North Star coordinates planning information, foundations, structure, envelope, services and interior fit-out as one buildable package.
Service area
North London
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What North Star coordinates
Feasibility
Review layout, drainage, foundations, neighbours and access.
Planning
Coordinate scale, roof form, materials, privacy and amenity.
Structure
Resolve foundations, load paths, openings and temporary works.
Envelope
Detail roofs, windows, insulation and weathering junctions.
Services
Check capacity and coordinate routes across both floors.
Handover
Commission, snag and provide the agreed completion records.
Test the whole-house layout first
A two-floor addition affects more than the rooms inside its footprint. Ground-floor circulation, kitchen and garden connections must align with bedrooms, bathrooms, stairs and service routes above. The design is tested as one house rather than two separate extensions.
Measured surveys, drainage information, trial holes and structural review establish the existing conditions. Foundation choices, sewer positions, neighbouring structures and site access can materially affect feasibility and construction sequence.
Window positions and room depths are studied for daylight, privacy and outlook. Useful wall space, furniture, storage and bathroom layouts are resolved before the elevations and structure are finalised.
Planning, neighbours and approvals
Double-storey proposals can have a greater effect on neighbour outlook, daylight, privacy and the appearance of the original house. Scale, roof form, materials and the relationship to boundaries are developed with the local planning context in mind.
Permitted-development rules include specific limitations for multi-storey enlargements, and conservation areas or removed rights can change the route. Planning status must be confirmed for the actual property and complete proposal.
Building Regulations, Party Wall procedures, drainage approvals, freeholder consent and covenants remain separate checks. Their timing is included before excavation, steel and long-lead products are committed.
Foundations, structure and envelope
The engineer coordinates foundations, load paths, openings and roof structure with the existing building. Temporary support and stability are planned before demolition, with inspection stages kept visible until approval is recorded.
Floor zones, beams and service penetrations are aligned so ceilings, windows, bathrooms and joinery remain buildable. Fire stopping, acoustic separation and insulation are inspected before linings conceal them.
Walls, roofs, windows and old-to-new junctions form one weathering system. Flashings, outlets, cavity trays, airtightness and movement details are checked before finishes begin.
Services, interiors and handover
Additional rooms can change heating, hot-water, electrical and drainage demand. Capacity and distribution routes are reviewed early, then coordinated with kitchens, bathrooms, lighting and fitted furniture.
North Star tracks samples, final dimensions and specialist lead times, protects completed areas and stages snagging. Testing, commissioning, approvals and agreed product information are organised for handover.
Frequently asked questions
Does a double-storey extension need planning permission?
Many do. Permitted-development rules contain detailed limits and restrictions, so the address, existing house and complete proposal require a specific check.
How are new foundations selected?
The engineer and project team use ground, load, drainage, tree and neighbouring-foundation information to determine an appropriate design and inspection plan.
Can the extension include bedrooms and bathrooms?
Yes. Room layouts, drainage, ventilation, hot water, electrics, structure and fire-safety details need to be coordinated early.
How are neighbours considered?
Massing, outlook, daylight, privacy, Party Wall matters, access and construction logistics are reviewed through the relevant design and project processes.
Can North Star deliver the complete fit-out?
Yes. The agreed scope can cover shell, services, bathrooms, joinery, flooring, decoration, commissioning, snagging and handover.
Discuss your project with North Star
Send the property postcode, proposed scope, available drawings and preferred timing. We will explain the practical next step and the information needed for a dependable quotation.
Request a consultationOffice: 020 3797 6399Mobile / WhatsApp: 07883 535012