Double Storey Extension Drawings in Kenton HA3
Fixed-fee, MCIAT-chartered double storey extension drawings for Kenton (HA3) homeowners — London Borough of Harrow validation and local constraints handled from the start.
Kenton (HA3) is a 1930s semi-detached suburb straddling the Harrow–Brent border, where the everyday project is a rear kitchen extension, a hip-to-gable or L-shaped dormer loft, or a two-storey side extension that adds a bedroom while keeping the interwar frontage in proportion.
Around the Mount Stewart and Northwick Circle conservation areas we take extra care with roof form, materials and the building line, and we always confirm whether an address falls to Harrow Council so the application is validated first time.
Planning in Kenton (HA3): what to know before you apply
No published householder Article 4 direction, though the Mount Stewart and Northwick Circle conservation areas curb some permitted-development rights; the main watch-points are matching the semi-detached roofline and confirming the correct authority near the Harrow/Brent boundary.
Typical Kenton housing stock
Interwar semi-detached and short terraced houses laid out as a 1930s suburb straddling the Harrow and Brent border, typically with bay windows, hipped roofs and off-street parking. Plots are regular with modest-to-generous rear gardens well suited to single-storey additions.
Streets we regularly draw for in Kenton
The Ridgeway · Draycott Avenue · Windermere Avenue · Northwick Circle
What HA3 is actually built of
Measured from 245 classified residential buildings in HA3, not from a description of the area.
Kenton HA3 housing mix
Residential building form across the HA3 postcode district, from 245 classified buildings.
| Attached on more than one side | 41% |
|---|---|
| Attached on one side | 51% |
| Detached | 9% |
| Median building footprint | 72 m² |
| Addresses per buildingAbove about 2 means flats and maisonettes dominate | 1.18 |
| Buildings classified | 245 |
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 Kenton (HA3) 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.
| 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 Kenton HA3 — FAQs
How much does a double storey extension cost to design in London?+
Do I need planning permission to add a second storey?+
Will a double storey extension overlook my neighbour's garden?+
Do I need an architect for a double storey extension?+
How long does it take to get double storey extension drawings?+
Do I need planning permission for a loft conversion in Harrow?+
What does Harrow expect for a rear extension on a 1930s semi?+
Can I extend a home in Harrow on the Hill or Pinner?+
How long does Harrow Council take to decide?+
How much do planning drawings cost in Harrow?+
Get your free Kenton planning assessment
Tell us your Kenton (HA3) address and ambition — we'll confirm feasibility, local constraints and a fixed fee within one working day.