
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.
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.


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
| Option | What it adds | Typical fee |
|---|---|---|
| Single-storey rear extension | A ground-floor kitchen-diner only, may qualify for permitted development | see Rear Extension Drawings, from £1,100 |
| Double storey side or rear extension | Two rooms across two floors, usually needs full planning | Full Planning pack ~£1,600–£2,400 |
| Double storey + Building Regulations (structural) | Combined pack including structural calculations for two-floor loads and foundations | Planning + Building Regs pack ~£2,200–£3,850 |
| Wraparound (rear + side return) | Combines two single-storey extensions into one L-shaped ground floor | see Wraparound Extension Drawings, from £2,200 |
Double Storey Extension Drawings in Wealdstone HA3 — FAQs
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