Layout and the existing house
Compare the proposed footprint with circulation, existing openings and the rooms that remain. A larger room is useful only if the whole ground floor works well.
Canonbury · N1 · House Extensions
House
extensions
in Canonbury, N1
Updated 14 July 2026
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Independent surveying by our sister practice, Hampstead Chartered Surveyors (RICS Firm No. 923064)Plan a kitchen, dining or garden-room extension to a Canonbury house around the original rear elevation, the space at the side and the garden you intend to keep. Bring Hampstead Renovations a sketch or survey of the ground floor, photographs of the garden side and a list of what the new space must do, and we can plan the next steps together.
Planning-led consent strategy
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Canonbury extension specialists
In-house RIBA Chartered Architects
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£10M insurance
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Independent surveying via Hampstead Chartered Surveyors
A considered approach to house extensions in Canonbury
Start a house extension with the change you want to make to daily life: a better kitchen and dining arrangement, a practical utility space or a stronger connection to the garden. Compare that goal with the original house, earlier additions and the space that should remain outside.
A useful brief connects room layout with daylight, neighbour relationships, structure, drainage and access. It should explain which work is included, which decisions are still open and which investigations or approvals are needed before construction.
Planning a house extension in Canonbury
Draw the whole side and rear of the house, including earlier additions and the boundary, then confirm the conservation area and any listing before fixing a footprint. East Canonbury sets its own side-extension limits for named streets.
Side extension limits
Canonbury’s guidelines keep single-storey side extensions to 3 m high and 3 m or more behind the front corner; a two-storey one must be no wider than 2 m and leave at least 3 m to the boundary. Each needs its roof behind a parapet.
Rear extension height and width
The Canonbury guidelines do not normally permit a full-width rear extension above one storey, or a half-width one above two, unless it is shown to cause no harm. In a conservation area, householder rights exclude side extensions and rear extensions of more than one storey.
Resolve the whole space before specifying the finish
Structure and drainage
Identify load-bearing alterations, likely foundation investigations and existing drains before fixing the layout. Specify the necessary design work for the actual site rather than assuming a standard foundation solution.
Garden and neighbours
Consider retained outdoor space, trees, levels, overlooking and neighbouring windows together. Include the consequences of glazing and rooflights in the design discussion.
Envelope and internal finishes
Coordinate the roof, walls, glazing, insulation and ventilation with kitchen, utility and joinery choices. Keep allowances and exclusions clear so quotations describe comparable work.
From the initial brief to a coordinated project
Define the brief and constraints
Record the full address, existing layout, prior alterations and intended use. Establish ownership, planning history, local controls and any relevant private agreements.
Develop and test the design
Compare options for the footprint, openings and garden connection. Resolve the necessary structural, drainage and building-control design with the approval route.
Plan construction around the home
Agree deliveries, storage, temporary protection and access to essential facilities. Base sequencing and programme on the actual scope and site arrangements.
Inspect, review and document
Agree required inspections and how design changes will be recorded. Keep the relevant approvals, installation information and completion documentation with the property records.
What to bring to your first conversation
- The address, existing plans and photographs of the rear, side, garden and neighbouring relationship.
- The intended room use, priorities for retained outdoor space and any known drainage or tree constraints.
- Available planning history, ownership or lease documents, access arrangements and occupation requirements.
Include the joinery in the design brief
Discuss fitted storage, wardrobes, shelving and cabinetry alongside the room dimensions, doors, heating and sockets. Historic fabric and fire-resisting elements need their own specification and approval checks.
Explore bespoke joineryHouse extensions: practical questions
Does every house extension require a planning application?
No. Some qualify for permitted development, but eligibility depends on the building, proposal and restrictions. Conservation-area rules treat side and multi-storey rear extensions differently from some single-storey rear work. Flats do not have Part 1 householder rights.
Is planning permission the same as Building Regulations approval?
No. Building Regulations cover construction and extension work, while planning addresses whether development is acceptable. The project may need both, alongside any separate listed-building, lease or private consent.
Will Party Wall procedures apply?
They may apply to work on a party structure, boundary building or qualifying excavation near a neighbour’s foundations. Assess the proposed work rather than assuming every extension needs an award. Minor drilling for shelves or cabinets is a different matter.
Can work to a listed house be treated like an ordinary extension?
The effect on its special architectural or historic interest must be assessed. Listed-building consent can be relevant to internal alterations as well as the addition, and should be considered before significant fabric is changed.
Where should the two-storey part of a rear extension go in East Canonbury?
The East Canonbury guidelines take the same approach to rear extensions as Canonbury and say that any two-storey part should normally sit on the staircase side of the rear elevation. They also set side-extension limits for a list of named streets, so check whether yours is one of them before drawing the footprint.
Can a garage or car-port be added at the front of a Canonbury house?
The Canonbury guidelines do not permit new garages or car-ports at the front of properties, and they do not normally allow front basement areas to be filled in or entrance steps to be widened. Look for extra space at the side or rear instead, within the separate limits that apply in those positions.
For examples of our wider renovation work, browse the portfolio. Discuss which details are relevant to your proposed project when you enquire.
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