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.
Dartmouth Park · NW5 · House Extensions
House
extensions
in Dartmouth Park, NW5
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 living-space extension to a Dartmouth Park house that stays subordinate to the original building without taking an excessive share of the garden. Hampstead Renovations can look at your plans with you, starting from the rooms that need to work better and the garden you would like to keep.
Planning-led consent strategy
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Dartmouth Park 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 Dartmouth Park
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 Dartmouth Park
Show how the addition relates to neighbouring rear elevations and how much garden remains, since both are tested here. On a slope, extending the ground floor with excavation can bring Camden’s basement policy into play.
Rear pattern and side gaps
The appraisal says rear extensions that depart significantly from the historic pattern of rear elevations will be refused, and the Council resists building in gaps between semi-detached or detached houses, at road junctions, at terrace ends and in corner-plot gardens.
Side and two-storey extensions
Camden’s Home Improvements guidance confirms that conservation-area houses have no permitted-development rights for side or two-storey extensions, and the larger rear-extension route is unavailable; Policy DC4 then expects any addition to stay subordinate.
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.
Can I build a side extension to a semi-detached Dartmouth Park house?
Conservation-area houses have no permitted-development right for a side extension, so planning permission is needed. The appraisal resists building in gaps between semi-detached or detached houses, and Policy DC4 says side extensions must not block or largely infill those gaps, so test the gap’s contribution to the street first.
Does digging into the slope for a ground-floor extension count as a basement?
It can. Camden’s basement guidance treats extending a ground floor into the slope with excavation as underground development, so the basement policy, including a Basement Impact Assessment, may apply. A storey reached at ground level on one side is generally not a basement unless the site was excavated to create that access.
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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We hold £10 million public liability insurance with Aviva; the certificate is available on request.
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