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Free 2026 London Planning ReportNew Build Drawings in Marylebone W1U

Marylebone W1U mansion flats and Harley Street terraces in Westminster City Council's Harley Street conservation area
Marylebone · W1U · Westminster

New Build Drawings in Marylebone W1U

Fixed-fee, MCIAT-chartered new build drawings for Marylebone (W1U) homeowners — Westminster City Council validation and local constraints handled from the start.

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Marylebone (W1U) sits on the Portman and Howard de Walden estates, and the work is characteristically internal reconfiguration, mansion-flat alterations and change of use — nowhere more so than the Harley Street medical district, where consulting-room, office and residential uses are finely balanced. The terraced grain is consistent and closely protected, so schemes turn on sensitive interiors and correct use classification rather than external enlargement.

With the Harley Street, Portman Estate and East Marylebone conservation areas overlapping much of the district and many buildings listed, most projects involve conservation-area or listed-building consent, and the estate freeholders impose their own consent regime. We confirm the estate, listing grade and conservation boundary before drawing and prepare the application to Westminster City Council's validation standard.

Marylebone W1U mansion flats and Harley Street terraces in Westminster City Council's Harley Street conservation area
Isometric illustration of a Marylebone W1U home new build drawings design
Proposed floor plan
Marylebone W1U

Planning in Marylebone (W1U): what to know before you apply

There is no published householder Article 4 direction driving decisions in W1U; the real controls are the overlapping conservation areas, widespread listing, the Harley Street change-of-use context and the Portman and Howard de Walden estates' freeholder consent requirements, all of which we address alongside the council submission.

Typical Marylebone housing stock

Brick and stucco terraces laid out for the Portman and Howard de Walden estates, including the Harley Street medical quarter and generous mansion flats, with a strong grain of Georgian townhouses converted to consulting rooms, offices and apartments.

Streets we regularly draw for in Marylebone

Harley Street · Margaret Street · Foley Street · Cleveland Street

What the wider borough is built of

W1U has too few classified residential buildings to publish a district figure of its own, so we do not estimate one. The measured figures below are borough-wide and W1U is not among the districts they cover.

Borough-wide building mix

Residential building form across 5 of the borough's 6 postcode districts, from 1,043 classified buildings. W1U is below the publication floor and is excluded from these totals, so they describe the borough around it rather than the district itself.

Attached on more than one side88%
Attached on one side9%
Detached2%
Buildings attached on more than one side921
Detached buildings26
Buildings classified1,043
Postcode districts measured5

Source: Ordnance Survey National Geographic Database (derived statistics). Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Extracted 2026-08-17.

New Build Drawings for Marylebone (W1U) homes: the package and the process

A new dwelling is a full application rather than a householder one, and the drawing set reflects that: site layout with levels and boundaries, floor plans and elevations for the new building, sections showing how it sits in the ground, and street-scene elevations placing it against what is already there.

Two packages follow the approval — the planning set and the construction set — and they have to stay in step. Foundation design, drainage strategy, thermal performance and fire strategy are drawn for Building Control against the same geometry that was granted permission, so the built house matches the approved one.

An infill plot is designed against its neighbours. Plot width, the building line either side, and the ridge heights next door set what the new house can be — and on a tight urban site those constraints usually shape the design more than the brief does.

Is my plot suitable for a new build in London?

A feasibility assessment looks at plot size and shape, access, existing boundary conditions, relevant planning policy for the borough, and the likely impact of a new dwelling on neighbouring properties before any design work begins. Infill plots — a gap between existing buildings on a street — and backland plots — a garden or yard site behind existing houses, reached by a shared access — each raise different issues: infill schemes are usually judged on how well they match the scale, spacing and character of the street, while backland schemes are judged heavily on overlooking, garden loss for neighbours, and whether the access arrangement is acceptable. A feasibility study gives an honest view of whether a scheme is likely to succeed before you commit to full drawings.

What does pre-application advice add to a new build project?

Pre-application advice is a formal, paid process most London boroughs offer, where planning officers give written feedback on a proposed scheme before a full application is submitted. For a new build — where the principle of development itself is often the main issue, not just the design details — this feedback can be invaluable: it surfaces concerns around density, massing, daylight and sunlight or heritage context early enough to be addressed in the drawings, rather than discovered for the first time as a refusal reason months into a full application. We prepare and submit pre-application enquiries as part of the new build service where it is likely to strengthen the eventual planning application.

How do daylight, sunlight and overlooking affect a new build design?

London boroughs assess new dwellings against their effect on the daylight and sunlight reaching neighbouring homes and gardens, commonly using the 45-degree rule as an initial check on a proposal's massing and position relative to neighbouring windows, alongside more detailed daylight and sunlight assessment on sensitive sites. Overlooking and loss of privacy from new windows, upper floors or roof terraces are assessed similarly, and often shape decisions on window placement, floor-to-floor heights and the overall footprint and massing of the new building. Designing with these constraints from the earliest sketch stage, rather than adjusting for them after a refusal, is one of the main advantages of instructing feasibility and pre-application work before a full planning set.

New build project stages
StageWhat it establishesTypical fee guide
FeasibilityWhether the plot can support a new dwelling and the likely constraintsQuoted individually, from within the £2,500 new build fee
Pre-application adviceWritten borough feedback on the scheme before a full applicationQuoted individually alongside the planning fee
Full planning drawingsThe complete drawing set submitted for planning permissionFrom £2,500
Building regs and structuralConstruction-ready drawings and calculations for buildingFrom £2,200–£3,850, quoted once planning is settled
Sheet from a new build drawings package drawn for a Marylebone property in W1U, showing the existing and proposed arrangement at scale
A sheet from the new build drawings package we submit to Westminster City Council for Marylebone (W1U) properties.
FAQ

New Build Drawings in Marylebone W1U — FAQs

How much do new build drawings cost in London?+
New build drawings start from £2,500 for feasibility and a full planning drawing set on a straightforward infill or backland plot, with building regulations and structural drawings quoted separately once the planning design is agreed.
Can any garden or backland plot be built on in London?+
Not necessarily — backland and garden plots are assessed on access, overlooking, loss of garden amenity for neighbours and borough policy, and a feasibility assessment gives an honest early view of whether a scheme is likely to be supported.
Do I need pre-application advice before a full new build application?+
It is not mandatory, but for a new dwelling — where the principle of development is often the main issue — pre-application advice can surface concerns early enough to address them in the design, reducing the risk of refusal.
Do you handle building regulations and structural drawings for a new build, or only planning?+
Both — the full new build service covers planning, building regulations and structural drawings from one in-house team, so the design stays consistent from feasibility through to construction-ready drawings.
How long does a new build project take from feasibility to planning permission?+
This varies with site complexity and whether pre-application advice is sought, but a full planning application is determined within the statutory period the borough applies to the application type, once submitted via the Planning Portal.
Do I need planning permission for works in Westminster?+
Almost always. The great majority of Westminster falls within a conservation area and a high proportion of buildings are listed, so a full planning application — and often listed-building consent — is usually required even for modest works. Permitted development rarely applies. We screen conservation, listing and lease constraints for your address before recommending a route.
I live in a mansion block — what extra consent might I need?+
Much of Westminster's stock is mansion-block or garden-square terrace, and the lease frequently requires the freeholder's consent alongside planning for external alterations. We confirm the lease position early and design a scheme that satisfies both the freeholder and the council, since either can block an otherwise sound proposal.
Will I need a Basement Impact Assessment in Westminster?+
Usually, for below-ground works. The City Plan basement policy requires a basement impact assessment and limits scale. If you are considering a basement or lower-ground extension we flag the requirement early and coordinate the structural and drainage input so the application is complete when submitted.
How long does Westminster City Council take to decide?+
Westminster determines most householder applications within the statutory eight-week period once validated, though listed-building, basement and conservation cases frequently attract additional consultation. We prepare submissions to the council's exacting validation and design standards to avoid the drawing queries that cause most delays.
How much do planning drawings cost in Westminster?+
We agree a fixed fee before we start, typically around 30% below an architect's fee for the same council-accepted drawings, with free redraws until the council approves. Heritage-led, listed-building and basement schemes require more evidence than a standard extension, so we quote once we understand your address and scheme rather than by the hour.
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