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Free 2026 London Planning ReportDouble Storey Extension Drawings in Wealdstone HA3

Loft conversion and rear extension to a Victorian terraced house in Wealdstone HA3 in the London Borough of Harrow
Wealdstone · HA3 · Harrow

Double Storey Extension Drawings in Wealdstone HA3

Fixed-fee, MCIAT-chartered double storey extension drawings for Wealdstone (HA3) homeowners — London Borough of Harrow validation and local constraints handled from the start.

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Wealdstone (HA3) is defined by its origins as a Victorian and Edwardian railway-and-industrial town, which grew around the London & North Western Railway and major factories including the Kodak plant that opened in 1891, Winsor & Newton and Whitefriars Glass. That history left dense terraced worker housing close to the old factory sites, so most householder projects here are extensions, side returns and lofts on tightly planned terraces.

There is no conservation area covering Wealdstone — that is a genuine, verified fact, not an omission. Its planning character is instead shaped by the repeating grain of its terraced streets and by the London Borough of Harrow's householder design expectations, which favour keeping the original terrace rhythm, brickwork and roofline intact. We treat that terraced cohesion, rather than a conservation designation, as the reference point when we design an extension.

Demand for rear extensions, side infills and loft conversions is steady across streets like Adderley Road, Hibbert Road and Canning Road, where compact frontages and long gardens are typical. We check each property's permitted-development position against Harrow's borough-wide controls first, then prepare drawings that either stay within permitted development or are ready to validate as a full householder application.

Loft conversion and rear extension to a Victorian terraced house in Wealdstone HA3 in the London Borough of Harrow
Isometric illustration of a Wealdstone HA3 home double storey extension drawings design
Proposed floor plan
Wealdstone HA3

Planning in Wealdstone (HA3): what to know before you apply

Because Wealdstone's terraces repeat so consistently, Harrow assess extensions against the established street pattern, so matching original brick, render detail and roof form matters more than on a mixed-typology road. There is no conservation area and no local Article 4 direction, so many houses retain permitted development rights for rear and loft work — but the narrow frontages and shared party walls mean depth, height and neighbour impact are the points a householder application is judged on.

Typical Wealdstone housing stock

Victorian and Edwardian terraced worker housing built close to the former factory sites and the railway, with narrow frontages and long rear gardens, alongside interwar semi-detached houses on the outer roads. These compact terraces are what drives the steady flow of rear-extension, side-return and loft-conversion work across the district.

Streets we regularly draw for in Wealdstone

The Greenway · The Broadway · Montrose Road · Risingholme Road · The Bye Way · Adderley Road · Fisher Road · Hibbert Road · Aberdeen Road · Lorne Road · Canning Road · Wellington Road

Double Storey Extension Drawings for Wealdstone (HA3) homes: the package and the process

Every double storey extension drawings we prepare for an Wealdstone property is drawn to London Borough of Harrow’s validation standards and tuned to the HA3 constraints above. Here is what the drawing package covers and how the process runs from first survey to approval.

A double storey extension builds a second floor above a single-storey side or rear addition, typically adding a bedroom and bathroom upstairs over a widened kitchen or reception room below. Because the foundations and roof of a single-storey extension already carry most of the fixed cost of building, adding a floor on top is often the most cost-effective way to gain two rooms rather than two separate projects. The trade-off is scrutiny: a two-storey addition sits closer to eye level with neighbouring windows and gardens, so councils examine massing, roofline and boundary distance more closely than they would a single-storey extension.

DrawingsDirect draws double storey side and rear extensions for full planning and building regulations, with structural calculations for the additional floor load and foundations produced in-house by our MCIAT-chartered team, on a fixed fee. If a single storey is enough, see our Rear Extension and Side Return Extension pages, or combine both with a Wraparound if you are extending sideways as well as up.

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
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
FAQ

Double Storey Extension Drawings in Wealdstone HA3 — 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 to extend a house in Wealdstone?+
Not always. Many Wealdstone terraces and interwar semis retain permitted development rights, so a modest single-storey rear extension, a side return or a rear loft conversion can often proceed without a full planning application. Because the frontages are narrow and the terraces sit close together, we check your property's size limits and party-wall lines against Harrow's controls first, and prepare a full householder application where the project goes beyond permitted development.
Is Wealdstone in a conservation area?+
No. There is no conservation area covering Wealdstone. Its planning character is shaped instead by its Victorian and Edwardian terraced street pattern and Harrow's householder design expectations, which favour keeping the original terrace rhythm, brickwork and roofline intact when you extend.
How much do planning and building-regulation drawings cost for a Wealdstone extension?+
We work to fixed fees agreed before we start, with a typical turnaround of around seven days for a standard rear extension, side return or loft on a Wealdstone house. As a chartered architectural technologist practice we produce the same council-accepted planning and building-regulation drawings as an architect, usually for a lower fee, and include free redraws until your application is approved.
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