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Free 2026 London Planning Report — Double Storey Extension Drawings in Balham SW12

Single-storey rear extension onto a garden behind a Balham SW12 Victorian terrace in Wandsworth
Balham · SW12 · Wandsworth

Double Storey Extension Drawings in Balham SW12

Fixed-fee, MCIAT-chartered double storey extension drawings for Balham (SW12) homeowners — London Borough of Wandsworth validation and local constraints handled from the start.

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Balham (SW12) is one of Wandsworth's most consistent Victorian and Edwardian terraced neighbourhoods, and side-return and rear extensions are by far the most requested projects here. Because so many houses share the same footprint, Wandsworth's design expectations for the area are well established — meeting them first time is straightforward when the drawings are prepared to the borough's residential extension guidance.

The Heaver Estate around Nightingale Lane is a conservation area, so roofline changes, dormers and front-elevation work there face tighter control than on the surrounding streets. We check where a Balham property sits relative to that boundary before recommending a permitted-development or full-application route.

Single-storey rear extension onto a garden behind a Balham SW12 Victorian terrace in Wandsworth
Isometric illustration of a Balham SW12 home double storey extension drawings design
Proposed floor plan
Balham SW12

Planning in Balham (SW12): what to know before you apply

SW12 has no borough-wide Article 4 direction affecting typical householder work, so many Balham houses retain permitted development rights for rear and loft projects — but the Heaver Estate conservation area is the exception, and terraced side-returns are common enough that Wandsworth has clear, well-documented expectations for them.

Typical Balham housing stock

Long runs of late-Victorian and Edwardian terraces on the streets between Balham High Road and Wandsworth Common, plus the red-brick Heaver Estate and a scattering of Edwardian mansion flats.

Streets we regularly draw for in Balham

Balham High Road · Bedford Hill · Ritherdon Road · Nightingale Lane

Double Storey Extension Drawings for Balham (SW12) homes: the package and the process

Every double storey extension drawings we prepare for an Balham property is drawn to London Borough of Wandsworth’s validation standards and tuned to the SW12 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

Also in Balham SW12

Planning PermissionPlanning DrawingsArchitectural DrawingsBuilding Regulations DrawingsLoft Conversion DrawingsDouble Storey Extension Drawings across WandsworthDouble Storey Extension Drawings across London
FAQ

Double Storey Extension Drawings in Balham SW12 — 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 Wandsworth?+
On many of Wandsworth's Victorian terraces a single-storey side-return or rear extension can fall within permitted development, so a full application isn't always required. Conservation areas such as Wandsworth Common and Nightingale Lane, and the 'between the commons' streets, can restrict this. We check your street's designation first and can secure a Lawful Development Certificate where the work is permitted development.
What does Wandsworth's basement Article 4 direction mean for me?+
In parts of Wandsworth an Article 4 direction removes permitted development for basement works, and the council requires a Basement Impact Assessment covering structural stability, drainage and groundwater. If you are considering a basement or lower-ground extension we flag whether the direction applies to your address early, and coordinate the structural input so the application is complete when submitted.
How long will Wandsworth take to decide my application?+
Wandsworth determines most householder applications within the statutory eight-week window once the submission is validated. Because the terraced grids around the commons are party-wall-sensitive and design expectations are well established, the commonest delay is a drawing query — so we prepare Wandsworth submissions to the validation checklist to keep them moving.
Can you design an extension for a converted flat near the commons?+
Yes. Much of Battersea and the streets around Clapham and Wandsworth Commons are mansion blocks and converted flats, where ownership, lease and party-wall considerations shape what is deliverable alongside the planning route. We confirm the ownership and structural context before drawing, and coordinate the calculations in-house so party-wall-sensitive schemes are handled cleanly.
How much do Wandsworth planning drawings cost?+
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 Wandsworth approves. The price depends on the scheme — a side-return differs from a mansard loft or a basement — so we quote once we have seen your project rather than charging by the hour.
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