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Free 2026 London Planning ReportDouble Storey Extension Drawings in Wembley HA9

Interwar semi-detached house with a rear extension in Wembley HA9, London Borough of Brent
Wembley · HA9 · Brent

Double Storey Extension Drawings in Wembley HA9

Fixed-fee, MCIAT-chartered double storey extension drawings for Wembley (HA9) homeowners — London Borough of Brent validation and local constraints handled from the start.

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Wembley (HA9) is largely an interwar suburb of semi-detached and terraced houses on the avenues around the stadium, where rear and side extensions and hip-to-gable loft conversions are the everyday projects. The regular plot pattern means Brent's design expectations for family extensions are well established, and meeting them first time is straightforward with drawings prepared to the borough's householder guidance.

Closer to Wembley Park the picture shifts toward denser flats and active regeneration, and the Wembley High Street conservation area adds tighter control over the historic town-centre frontages. We establish which context a Wembley property sits in — suburban avenue or higher-density regeneration edge — before recommending a route and preparing the application to Brent's validation standards.

Interwar semi-detached house with a rear extension in Wembley HA9, London Borough of Brent
Isometric illustration of a Wembley HA9 home double storey extension drawings design
Proposed floor plan
Wembley HA9

Planning in Wembley (HA9): what to know before you apply

HA9 carries no published householder Article 4 direction affecting typical extensions, so many Wembley semis retain permitted development rights for rear and loft work — but the Wembley High Street conservation area is the exception, and denser sites near the stadium attract closer amenity scrutiny.

Typical Wembley housing stock

Interwar semi-detached and terraced houses on the residential avenues north and east of the stadium, mixed with a growing amount of denser flatted development around Wembley Park and the regeneration zone.

Streets we regularly draw for in Wembley

Bovingdon Avenue · Flamsted Avenue · Tring Avenue · Berkhamsted Avenue

What HA9 is actually built of

Measured from 194 classified residential buildings in HA9, not from a description of the area.

Wembley HA9 housing mix

Residential building form across the HA9 postcode district, from 194 classified buildings.

Attached on more than one side38%
Attached on one side55%
Detached7%
Median building footprint70 m²
Addresses per buildingAbove about 2 means flats and maisonettes dominate1.23
Buildings classified194

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.

Double Storey Extension Drawings for Wembley (HA9) homes: the package and the process

At first-floor level the drawings have to answer for daylight, privacy and massing. That means proposed elevations showing every new window with its position relative to the boundary, a section taken through the extension and the neighbouring building, and a roof form drawn to sit below the existing ridge rather than compete with it.

We draw the neighbouring property alongside your own, because the officer's assessment is comparative — the effect on their windows and outlook is the test. Setting the first floor in from the boundary, and showing that set-back as a dimension, resolves most objections before consultation begins.

At first floor the boundary relationship decides everything. A detached house has room to set the addition in on both sides; a semi has one shared wall and one clear flank; a mid-terrace can usually only go to the rear, where the effect on both neighbours has to be drawn.

Do I need planning permission for a double storey extension in London?

Almost always. Permitted development rights for two-storey extensions are far more restrictive than for single-storey work, particularly on how close the new structure can come to a boundary and how closely its roof pitch and eaves height must match the existing house, so most double storey projects are drawn and submitted as full householder planning applications rather than relying on permitted development.

Where the property sits in a conservation area or is subject to an Article 4 direction, any remaining permitted development allowance for a second storey is typically removed entirely, reinforcing the need for a full application. We check your property's status and your borough's design guidance before drawing.

How do councils control the impact of a double storey extension on neighbours?

Because a second storey introduces new windows and massing at first-floor level, London boroughs apply design guidance aimed specifically at protecting neighbouring light, privacy and outlook.

  • The 45-degree rule, tested at neighbouring windows, to check the extension does not block an unreasonable amount of daylight
  • A common design expectation that a two-storey side extension is set in roughly 1 metre from the shared boundary, rather than built hard against it
  • A first floor commonly set back from the ground floor front elevation, so the upper storey reads as subordinate to the main house from the street
  • Obscure or high-level glazing on flank walls facing directly into a neighbour's garden or windows, to limit overlooking

Matching the roofline and materials

Planning officers assess a double storey extension heavily on how convincingly it reads as part of the original house rather than an addition bolted onto the side. Our drawings match ridge height, roof pitch, eaves detail and brick or render finish to the existing building wherever the design brief allows, which is consistently one of the strongest factors in securing approval without delay or redesign. Where a subtly contrasting material is proposed instead — a different brick tone, or a zinc or slate roof against a tiled original — we set it out clearly on the elevations so the design intent reads as deliberate rather than a mismatch, which is how most London boroughs prefer a genuine design statement to be presented.

Extending once vs twice: single versus double storey
OptionWhat it addsTypical fee
Single-storey rear extensionA ground-floor kitchen-diner only, may qualify for permitted developmentsee Rear Extension Drawings, from £1,100
Double storey side or rear extensionTwo rooms across two floors, usually needs full planningFull Planning pack ~£1,600–£2,400
Double storey + Building Regulations (structural)Combined pack including structural calculations for two-floor loads and foundationsPlanning + Building Regs pack ~£2,200–£3,850
Wraparound (rear + side return)Combines two single-storey extensions into one L-shaped ground floorsee Wraparound Extension Drawings, from £2,200
Sheet from a double storey extension drawings package drawn for a Wembley property in HA9, showing the existing and proposed arrangement at scale
A sheet from the double storey extension drawings package we submit to London Borough of Brent for Wembley (HA9) properties.
FAQ

Double Storey Extension Drawings in Wembley HA9 — FAQs

How much does a double storey extension cost to design in London?+
Double storey extension drawings start from £2,400, covering full planning permission and structural design for the additional floor. A combined planning and building regulations package with full structural calculations runs up to around £3,850, fixed and agreed upfront.
Do I need planning permission to add a second storey?+
In almost all cases, yes. Permitted development rights for two-storey extensions are much tighter than for single-storey work, particularly around boundary distance and roof matching, so we design double storey projects on the assumption a full householder planning application is required.
Will a double storey extension overlook my neighbour's garden?+
That is exactly what planning officers check, using the 45-degree daylight rule alongside boundary set-in and first-floor set-back guidance. Where a new flank window would look directly into a neighbour's garden, we typically specify obscure or high-level glazing to address it before submission rather than after an objection.
Do I need an architect for a double storey extension?+
No. DrawingsDirect is an MCIAT-chartered architectural technologist practice, producing the same council-accepted drawings and in-house structural coordination as an architect, for a fixed fee typically around 30% lower, with structural calculations for the additional floor produced by the same team rather than a separately appointed engineer.
How long does it take to get double storey extension drawings?+
Drawings are typically ready around 7 days from survey. A householder planning application then has a statutory 8-week determination period once submitted.
Do I need planning permission for a side-return extension in Brent?+
On the Victorian and Edwardian terraces of Kilburn, Willesden and Harlesden a single-storey side-return or rear extension can fall within permitted development, so a full application isn't always needed. Conservation areas such as Queen's Park and Mapesbury restrict this. We check your street's designation first and can confirm permitted development with a Lawful Development Certificate where it qualifies.
What does Brent's borough-wide HMO Article 4 direction affect?+
Brent applies a borough-wide Article 4 direction removing permitted development rights for change of use to an HMO (C3 to C4), so a conversion to a house in multiple occupation needs a full application anywhere in the borough. It doesn't affect a standard family extension or loft, but we confirm whether it applies to your intended use before advising.
Is a hip-to-gable loft conversion allowed on my Brent semi?+
Frequently, yes. The interwar semis of Wembley, Kingsbury and Sudbury suit hip-to-gable and dormer conversions, which often qualify as permitted development within the volume limits. We confirm eligibility against those limits and any conservation or Article 4 constraint, then produce the planning and building-regulations drawings.
How long does Brent Council take to decide?+
Brent determines most householder applications within the statutory eight-week period once validated; conservation cases can attract additional consultation. The dense terraced streets are party-wall-sensitive, so the commonest delay is a drawing query — we prepare submissions to the council's householder guidance to keep them moving.
How much do planning drawings cost in Brent?+
We agree a fixed fee before starting, usually around 30% below an architect's fee for the same council-accepted drawings, with free redraws until Brent approves. A side-return, a hip-to-gable loft and a conservation-area application differ in complexity, so we quote once we understand your street and project rather than by the hour.
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