Builders
in Marylebone, W1
Architects, Engineers, Surveyors & Builders Under One Roof.
Surveyor-led refurbishment advice via Hampstead Chartered Surveyors →One Studio. One Contract. One Team.
We deliver Marylebone building projects with an integrated design-build team under one fixed-price contract - RIBA design, structural engineering, party wall coordination, procurement, directly managed site teams, Building Control, programme control and final handover through one accountable fixed-price contract.
Building work in Marylebone, W1U opens with a question few other districts ask: whose estate is the house on? Much of W1 sits on the Portman and Howard de Walden estates, and on the estate terraces works are agreed with both Westminster and the freeholder under a clear consent strategy. The designations run deep: the Harley Street Conservation Area — designated in 1968, extended in 1981 — covers the Howard de Walden Estate's grid, while the Portman Estate Conservation Area, designated in 1967, protects the 18th-century squares laid out from Portman Square in 1764 to Manchester Square and Baker Street.
What those layers protect is one of London's most complete Georgian quarters: brick townhouses on Montagu Square and Bryanston Square, the leafy Regency set-piece of Dorset Square, and the mansion flats and conversions above the shops of Marylebone High Street — stock that is largely listed and leasehold, where the mansion blocks add freeholder and party-wall layers of their own. Below ground, Westminster's city-wide basement Article 4 direction, in force since July 2016, means basement schemes need planning permission.
Even the ground and the sky are regulated: the Marylebone Village Area of Special Archaeological Priority sits around the north end of the High Street, and the strategic view from Primrose Hill to the Palace of Westminster passes through the conservation area. Leading with the consent strategy is what keeps a Marylebone scheme on track.
Builders in Marylebone: Applied to the Local Stock
The Harley Street Conservation Area - first designated in 1968 around Portland Place, Harley Street and Wimpole Street, and extended west to Marylebone High Street in 1981 - covers the Howard de Walden Estate's Marylebone grid, with medical uses of international renown in and around Harley Street and Marylebone High Street as its main shopping thoroughfare; it is bounded by the Regent Street, Mayfair, Portman Estate, Regent's Park and East Marylebone conservation areas. The Portman Estate Conservation Area was first designated in 1967 to cover the late 18th and early 19th century residential area developed by the Portman Estate, and was extended in 1979 to include parts of Seymour Place and Marylebone Road and in 1990 to include Portman Square; Portman Square was laid out in 1764 and the estate's characteristic 18th century grid extended to Manchester Square (1776) and Baker Street (completed c. 1800). The Marylebone Village Area of Special Archaeological Priority lies largely within the Harley Street Conservation Area around the north end of Marylebone High Street, and the strategic view from Primrose Hill to the Palace of Westminster cuts through the conservation area from Park Crescent to Oxford Street.
Sources: Westminster City Council, Harley Street conservation area mini guide (May 2004) (2026); Westminster City Council, Portman Estate conservation area mini guide (May 2004) (2026)
What Our Building Service Covers
Hiring a builder should mean hiring one accountable team, not refereeing a chain of subcontractors. As a design-and-build practice we carry your project from drawings to handover under a single fixed-price contract, with the architect, engineer and site manager answerable to the same programme. The scope below covers most of the building work we are asked to price.
- Extensions — rear, side-return and wraparound additions, built weathertight before the existing house is opened up
- Loft & basement conversions — new storeys above and below, with steelwork and waterproofing engineered in-house
- Structural alterations — load-bearing wall removals, new openings and floor changes with calculations done before pricing
- Refurbishment — whole-house or single-floor upgrades sequenced so trades never queue behind each other
- Kitchens & bathrooms — first fix to final silicone, delivered by the same teams who built the rooms around them
- Mechanical & electrical — rewires, heating systems and ventilation installed and certified as part of the main contract
- Joinery & carpentry — doors, staircases, skirting and fitted furniture made to suit the age of the building
- External & facade works — brickwork, render, roofing repairs and landscaping tied into the main programme
How We Run Your Project
Six checkpoints between first phone call and final handover, each signed off before the next starts.
- Site visit & scope — we walk the property with you, test what the budget can realistically deliver and flag constraints early.
- Drawings & approvals — our architects prepare the design and handle whatever consents the work requires.
- Itemised fixed price — every trade, material and provisional sum listed line by line, so nothing is priced twice.
- Mobilisation — protection, welfare, neighbour notifications and deliveries organised before the first skip arrives.
- The build — structural work, first fix, second fix and finishes run by a dedicated site manager you can reach directly.
- Handover — a walked snagging inspection, full certification pack and aftercare contact once the site is cleared.
Almost all building work of this scale needs Building Regulations approval — structural openings, electrics, drainage, heating and fire safety are each inspected and certified through building control, which we manage on your behalf. Where the works cut into, bear on or excavate near a wall shared with a neighbour, the Party Wall etc. Act 1996 obliges you to serve notice before starting, and we coordinate the surveyors so the programme is not held hostage to it. Our planning guide library sets out what applies borough by borough.
Why Hampstead Renovations
The word “builder” covers everything from a van and a ladder to a full construction practice, so credentials matter. Ours: design by our in-house RIBA Chartered Architects, structural calculations from our own chartered structural engineers, and RICS surveying support through our sister company, Hampstead Chartered Surveyors, for party wall and condition matters. Every project runs on a fixed-price JCT contract, carries £10M public liability insurance, and is backed by a 12-month defects period plus a 10-year workmanship warranty. Enquire before 2pm on a weekday and we will call you back the same day.
Builders in Marylebone: Questions
Who has to approve building work in Marylebone?
Often more than the council. Westminster scrutinises external change, but on the Portman and Howard de Walden estate terraces works are agreed with both Westminster and the freeholder — so the consent strategy covers estate and planning tracks together — and the mansion blocks add freeholder and party-wall layers on top.
Which conservation areas cover Marylebone?
Two big ones between them cover most of the district. The Harley Street Conservation Area (designated 1968, extended 1981) takes in the Howard de Walden Estate's grid from Portland Place across to Marylebone High Street, and the Portman Estate Conservation Area (designated 1967, extended in 1979 and 1990) covers the estate's characteristic 18th-century grid around Portman Square, Manchester Square and Baker Street. The Marylebone Village Area of Special Archaeological Priority adds a further layer near the High Street.
What kinds of Marylebone buildings do your builders work on?
The full W1 mix — Victorian terraces, mansion flats, mews houses and period residential streets, with projects ranging from compact leasehold flats to carefully sequenced townhouse upgrades. The Georgian townhouses on the great squares, the estate terraces and the substantial mansion flats are largely listed and leasehold, so the building work and the approvals are planned as one job.
Can we build a basement in Marylebone?
Yes, but always through a planning application: Westminster's city-wide basement Article 4 direction, in force since 31 July 2016, removes permitted development rights for basement development throughout the city. On budget, London-wide guidance puts new excavation and underpinning at £2,100–£4,000 per square metre of excavated area, excluding full fit-out.
What does building work cost in Marylebone?
It depends on the building and the scope, but as headline ranges we use £90,000–£475,000 excluding VAT for a house renovation in Westminster and £60,000–£110,000 excluding VAT for a flat refurbishment. A scheme-specific figure follows once the consents and specification are scoped.
How do you differ from a standalone builder in Marylebone W1?
Most builders in Marylebone subcontract design, structural engineering and planning — leaving you managing four to six separate firms with overlapping responsibilities and gaps where things get dropped. We are one practice with every discipline in-house: RIBA chartered architects, surveying support through Hampstead Chartered Surveyors, IStructE chartered engineers and our own build teams. That means one contract, one point of responsibility, one fixed price. When an issue arises on site — a hidden beam, a changed specification, a neighbour request — it is resolved inside our office, without finger-pointing between separate firms with conflicting commercial interests.
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