Double Storey Extension Drawings in Whetstone N20
Fixed-fee, MCIAT-chartered double storey extension drawings for Whetstone (N20) homeowners — London Borough of Barnet validation and local constraints handled from the start.
Whetstone (N20) grew up along the Great North Road (the A1000) as a ribbon settlement, then filled out into a proper suburb once the Northern line reached Totteridge & Whetstone in the early twentieth century. The result is a genuinely mixed stock — Victorian and Edwardian houses fronting the old main road, and consistent interwar semi-detached homes on the streets behind — so a householder project has to respond to the particular character of its own street.
There is no conservation area covering Whetstone — that is a genuine, verified fact, not an omission. Its planning character is shaped instead by that arterial-suburb typology and by Barnet's householder design expectations, which favour keeping original building lines, bay-window frontages, materials and roof forms intact. We treat the character of your specific road, rather than a conservation designation, as the reference point when we design an extension.
Most of the work here is rear extensions, side infills and loft conversions on the interwar semis lining streets like Woodside Avenue, Buckingham Avenue and Oakleigh Park North. We check each property's permitted-development position against Barnet'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 Whetstone (N20): what to know before you apply
Because Whetstone mixes Victorian frontages with interwar semis, Barnet assess extensions against the character of the individual street, so matching brick, render, bay detailing and roof form matters. There is no conservation area and no local Article 4 direction, so many houses retain permitted development rights for rear and loft work — but shared building lines on the semis and the compact side-street plots mean depth, height and neighbour impact are the points a householder application turns on.
Typical Whetstone housing stock
Victorian and Edwardian houses front the old Great North Road, while interwar semi-detached and terraced homes fill the residential side streets behind. That split typology — older two-storey frontages on the arterial road and consistent 1920s–1930s semis on the estate roads — is what shapes most rear-extension and loft-conversion work here.
Streets we regularly draw for in Whetstone
Greenway · Southway · Swan Lane · Woodside Avenue · Friern Mount Drive · Maxfield Close · Buckingham Avenue · Langton Avenue · Well Grove · Oakleigh Gardens · Oakleigh Park North · Oxford Gardens
What N20 is actually built of
Measured from 391 classified residential buildings in N20, not from a description of the area.
Whetstone N20 housing mix
Residential building form across the N20 postcode district, from 391 classified buildings.
| Attached on more than one side | 23% |
|---|---|
| Attached on one side | 54% |
| Detached | 24% |
| Median building footprint | 93 m² |
| Addresses per buildingAbove about 2 means flats and maisonettes dominate | 1.42 |
| Buildings classified | 391 |
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 Whetstone (N20) 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 Whetstone N20 — 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 to extend a house in Whetstone?+
Is Whetstone in a conservation area?+
How much do planning and building-regulation drawings cost for a Whetstone extension?+
How long does Barnet take to decide an application?+
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