Flat
refurbishment
in Swiss Cottage, NW3
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Hampstead Chartered Surveyors & Building ConsultancySwiss Cottage flats range from mansion blocks and a 1920s apartment building to single floors of former villas, and each comes with its own lease and its own Camden rules.
On several roads east of Fitzjohn's Avenue, Camden's appraisal notes sizeable mansion blocks, more urban in feel but normally surrounded by planted grounds.
We refurbish flats in every one of these building types, and each job opens with three documents: the lease, the plans of the flats above and below, and the agreed route for the builders through the building.
Source: Camden: Fitzjohns/Netherhall Conservation Area Character Appraisal and Management Plan (December 2022)
The buildings Swiss Cottage flats are in
Eton Court on Eton Avenue is a brown brick apartment block of the 1920s, standing among red brick houses.
To the north of Adelaide Road, the residential towers of the Chalcots Estate dominate views from the Elsworthy streets.
Within the Elsworthy area, many houses that were divided during and after the war have since gone back to being family homes.
Netherhall Gardens, climbing from Finchley Road, has larger buildings than most, many of five and six storeys.
Where a flat is one floor of a former house, its roof, drains and party structures are usually shared, so we settle what belongs to the flat before a line is drawn.
Sources: Camden: Belsize Conservation Area Statement (agreed 20 November 2002), Camden: Elsworthy Road Conservation Area Appraisal and Management Strategy (adopted 14 July 2009), Camden: Fitzjohns/Netherhall Conservation Area Character Appraisal and Management Plan (December 2022)
What a flat needs planning permission for
A flat carries no householder permitted development rights, so anything that counts as development, an extension for instance, requires an application.
On the South Hampstead side, Camden's factsheet makes a new window or door of another material or design a planning matter anywhere on a flat, back or front.
It treats new rooflights on any part of a flat's roof, the rear slope included, the same way.
Applications made necessary only by the Article 4(1) direction carry no council fee for now.
If the work involves the building's front, remember that a property has just one front in Camden's terms: the principal elevation facing a road or public space, usually with the main door.
Sources: MHCLG: Permitted development rights for householders, Technical Guidance (September 2019), Camden: Swiss Cottage Conservation Area, what the new planning measures mean for you (Article 4(1) factsheet, 1 September 2010, updated June 2026)
The lease, the landlord and the neighbours
Under some leases a landlord's permission is needed for alterations even after planning permission and building control approval have been granted, LEASE explains.
Separate clauses may dictate finishes; a requirement for carpeted floors is one example.
If party wall work is notifiable and the neighbour does not agree, one or two surveyors settle in writing how and when it is done and who pays, which is a matter apart from planning and building control.
LEASE expects anyone altering a flat to keep noise in check and the common stairs and halls tidy and clear.
Sources: LEASE: alterations and home improvements, GOV.UK: Party walls and building work, LEASE: Alterations and home improvements
Heat, glazing and sound in older buildings
Mansion blocks, Camden's appraisal observes, need less heating, because the flats around each one act as insulation and share their warmth.
Where the Swiss Cottage design guide applies, inner secondary glazing needs no planning permission, its meeting rails lining up with the existing bars, and Camden reckons that, paired with well-fitting shutters, it can cut heat loss by 60%.
Double glazing a big-paned sash so it still looks original can sometimes be done, but it now needs planning permission.
Beneath new boards or stone we lay an acoustic layer and break the floor's contact with the walls, so footsteps stay in the flat.
Sources: Camden: Fitzjohns/Netherhall Conservation Area Character Appraisal and Management Plan (December 2022), Camden: Swiss Cottage Conservation Area Design Guide (updated June 2026)
Wiring, heating and water in a shared block
Rewiring a flat begins at the meter cupboard, which in many blocks sits in the common parts, so the managing agent's consent and the electricity supplier's booking are arranged together.
Where heating comes from a communal plant room, radiators are changed only with the system drained by the block's own engineer; where the flat has its own boiler, its flue position is agreed before the kitchen is designed.
Water is isolated at the flat's own stopcock, and if that valve is missing or seized we fit a new one before any other plumbing starts.
Running the work in a shared building
Camden allows noisy flat work without special authorisation from Monday to Friday, 8am to 6pm, plus Saturday mornings 8am to 1pm, but never on a Sunday or bank holiday.
Before materials come in, the lift, the stairs and the entrance hall are lined with boards and sheeting, and cleaned at the end of each day.
The managing agent is sent our method statement and our contact details before we start, and neighbours are told which days will be the noisiest.
Source: Camden Council: noisy building works
Questions about refurbishing a Swiss Cottage flat
Can my Swiss Cottage flat have new windows?
Like-for-like copies, yes; on the South Hampstead side a change of material or design needs planning permission.
Will the landlord have to agree to my plans?
Perhaps: LEASE says some leases require the landlord's permission even after planning and building control approval.
Is oak flooring possible in a mansion flat here?
Only if the lease allows it, since some leases require carpet.
Could my top-floor flat gain a rooflight?
Only with planning permission, whichever slope it is on.
On which days can a flat refurbishment be noisy?
Monday to Friday 8am to 6pm and Saturday 8am to 1pm, never Sundays or bank holidays.
What does a flat refurbishment in Swiss Cottage cost?
Your Swiss Cottage figure is confirmed after a feasibility visit.
Sources: Camden: Swiss Cottage Conservation Area Design Guide (updated June 2026), Camden: Swiss Cottage Conservation Area, what the new planning measures mean for you (Article 4(1) factsheet, 1 September 2010, updated June 2026), LEASE: alterations and home improvements, MHCLG: Permitted development rights for householders, Technical Guidance (September 2019), Camden Council: noisy building works
Related pages
Sources
- Camden: Fitzjohns/Netherhall Conservation Area Character Appraisal and Management Plan (December 2022)
- Camden: Belsize Conservation Area Statement (agreed 20 November 2002)
- Camden: Elsworthy Road Conservation Area Appraisal and Management Strategy (adopted 14 July 2009)
- MHCLG: Permitted development rights for householders, Technical Guidance (September 2019)
- Camden: Swiss Cottage Conservation Area, what the new planning measures mean for you (Article 4(1) factsheet, 1 September 2010, updated June 2026)
- LEASE: alterations and home improvements
- GOV.UK: Party walls and building work
- Camden: Swiss Cottage Conservation Area Design Guide (updated June 2026)
- Camden Council: noisy building works
Guides & Local Reading
Flat Refurbishment in Nearby Areas
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