Flat renovation
and refurbishment
in Marylebone, W1U
Architects, Engineers, Surveyors & Builders Under One Roof.
One Studio. One Contract. One Team.
Independent surveying by our sister practice, Hampstead Chartered Surveyors (RICS Firm No. 923064)Some of Marylebone's mansion blocks date from the late 19th century, when Westminster's guide says parts of the northern Portman Estate streets were rebuilt with them; other flats sit in the Harley Street grid, where we refurbished one on Wimpole Street. The Portman Estate notes that modernising a flat on its estate may need approval from both the immediate landlord and the freeholder, so those consents and the lease are settled before the layout.
The lease, the Portman licence and the list entry
Read the lease before any drawing. LEASE warns that some leases make an alteration subject to the landlord's permission whatever planning or building regulations approval exists, and that a carpet-only flooring clause could stop wood or laminate being laid even where other work is allowed.
Where the Portman Estate owns the freehold, its licence-to-alter FAQ is more specific. A tenant modernising a flat may need approval from the immediate landlord and from the freeholder. Because leases commonly limit floor finishes to carpet and underlay or another suitable material, ceramic tiles or hardwood may need a licence, and so may a satellite dish or air conditioning unit on the roof.
The estate charges a licence application fee that depends on the nature, extent and cost of the work. Where the work is structural, the lease may also leave the leaseholder paying the estate's solicitors' and consultant structural engineers' fees, and a premium may be payable.
Listing is a separate test. Westminster's Harley Street guide says almost all terraces and houses surviving from the first phase of building in anything like their original condition are listed, and City Plan Policy 44 asks that works to a listed building protect, or where appropriate restore, original or significant detail and historic fabric.
Sources: LEASE: alterations and home improvements, The Portman Estate: licence to alter, Westminster City Council: Harley Street conservation area mini guide, Westminster City Plan 2019-2040 (2026, adopted January 2026)
Converted houses, mansion flats and flats above shops
Many of Marylebone's original Georgian houses are now occupied by offices and flats, Westminster's 2008 Harley Street audit records, and the council's summary of the conservation area notes later infills among the Georgian terraces, including mansion flats from the Victorian and Edwardian eras.
On Marylebone High Street the same summary describes largely Edwardian and late Victorian flats and mansion blocks above shops. A flat there shares structure and services with the shop below, so the survey looks at the shop's ceiling and extract routes as well as at the flat itself.
In a flat made from a Georgian house, the front rooms keep the house's windows: recessed timber sliding sashes under flat brick arches, as the audit describes them, which are overhauled and draught-sealed rather than replaced.
Floors between converted flats are often the original joists and boards. Sound insulation is added from within the flat we are refurbishing, so the neighbours' ceilings below, which may carry historic plaster, are left undisturbed.
Sources: Westminster City Council: Harley Street conservation area audit (SPD, adopted 16 June 2008), Westminster City Council: Westminster's conservation areas, character summaries and overview
Mansion blocks and the Harley Street grid
In the Portman Estate Conservation Area, Westminster's 2004 guide records that the northern streets were partly redeveloped with mansion blocks in the late 19th century. The same area has about 600 listed buildings, chiefly around Bryanston, Montagu and Manchester Squares and along Gloucester Place.
The Harley Street Conservation Area, first designated in 1968 around Portland Place, Harley Street and Wimpole Street, is known for medical uses of international renown. Its guide counts two Grade I buildings, All Souls Langham Place and Chandos House, 33 at Grade II* and about 260 at Grade II.
The Portman Estate's planned 18th-century grid began with Portman Square in 1764 and reached Manchester Square in 1776. The London Squares Act 1931 protects Portman, Bryanston, Montagu and Manchester Squares, and Portman Square and Manchester Square are also Grade II registered historic parks and gardens.
A flat in either kind of building shares its floors, risers and entrance with neighbours. We lift a section of floor to see how it is framed before specifying stone or timber, find the shared stacks before a kitchen or bathroom moves, and agree with the managing agent how materials reach the flat.
Sources: Westminster City Council: Portman Estate conservation area mini guide, Westminster City Council, Harley Street conservation area mini guide (May 2004), Westminster City Council: Harley Street conservation area mini guide, Westminster City Council, Portman Estate conservation area mini guide (May 2004)
How a Marylebone flat refurbishment runs
The first step is a feasibility visit, then a measured survey and a read of the lease and title with you. Our in-house architects and designers plan the layout, services and floor build-up, our in-house structural engineers design any change to a structural wall or floor, and independent surveying is available from our sister practice, Hampstead Chartered Surveyors & Building Consultancy.
Licence applications go to the landlord and, where they hold the freehold, the estate, with listed building consent sought from Westminster where the list entry calls for it. You receive a written quotation with No Deposit Required, and building starts once each consent has been granted.
Marylebone flat refurbishment: questions
Will the Portman Estate need to approve my flat refurbishment?
Possibly, as well as your immediate landlord. The estate's licence-to-alter FAQ says modernising a flat may need approval from both, and that a structural alteration which changes the property's appearance may need planning permission and building regulations approval on top of a formal licence.
Can I replace the carpet with tiles or hardwood?
Only once the lease has been checked. The Portman Estate says leases commonly require floor finishes of carpet and underlay or other suitable material, so a tiled or hardwood floor may need a licence; LEASE makes the same point about carpet clauses in leases generally.
How long does a Portman Estate licence take?
The programme depends on the agreed scope, approvals, site conditions and procurement. Discuss the sequence of work at a feasibility visit.
When can noisy work happen in a Marylebone block?
The council's building hours run from 8am to 6pm, Monday to Friday, and from 8am to 1pm on Saturday. Noisy work on a Sunday or bank holiday needs special permission, and anything noisy outside the set hours needs a Section 61 consent obtained beforehand.
How much does a flat refurbishment cost in Marylebone?
A flat in Marylebone is priced on the lease and the block. The Portman Estate's licence or the landlord's, the managing agent's hours and lift rules, floor treatment above a neighbour, and where stacks and extract can run all decide the scope. We look through these with you at a feasibility visit; when the scope and specification are agreed, a written quotation follows.
Sources: The Portman Estate: licence to alter, LEASE: alterations and home improvements, Westminster City Council: noise problems we can investigate, Westminster City Council: Code of Construction Practice (May 2026)
Marylebone flat refurbishment we have completed
More flats of the same kind, nearby in Mayfair and St John's Wood:
Rooms and elevations typical of Marylebone
Design, joinery and the build, under one contract in Marylebone
The same team stays with the project from the first visit to handover. Our in-house architects, designers and structural engineers draw and specify the work. Master joiners make the fitted furniture. Building Regulations approval comes from the building control body appointed for the project. Independent surveying is a separate appointment: Hampstead Chartered Surveyors & Building Consultancy, our RICS-regulated sister practice, is a separate firm that a homeowner instructs directly. One JCT contract covers the building work. Electrical and gas work is carried out by appropriately registered engineers. Completed structural work carries a 12-month aftercare/defects period. Cover is £5M public liability, £10M employers' liability and contractors' all risks cover. Main office: 250 Finchley Road, Hampstead, London NW3 6DN. Central London client consultation address: 2 Eaton Gate, Belgravia, London SW1W 9BJ. Telephone 020 7101 3168.
Licence to alter · Independent surveying by our sister practice
What clients have said about the work
I would like to thank Ross and his team for their consistent commitment to quality and their unerring reliability.
We have worked with Ross and his company many times. They are extremely professional and hardworking individuals who can work under any circumstances. There was no variation to the works.
Verified Planning, Estate & Conservation Sources
- LEASE: alterations and home improvements
- The Portman Estate: licence to alter
- Westminster City Council: Harley Street conservation area mini guide
- Westminster City Plan 2019-2040 (2026, adopted January 2026)
- Westminster City Council: Harley Street conservation area audit (SPD, adopted 16 June 2008)
- Westminster City Council: Westminster's conservation areas, character summaries and overview
- Westminster City Council: Portman Estate conservation area mini guide
- Westminster City Council: noise problems we can investigate
Book a consultation
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Consultation
We survey your property, discuss your vision and provide a clear budget framework.