Georgian and Victorian townhouses off the King's Road in Chelsea SW3, where rear returns and basements are controlled by Kensington and Chelsea Council

Chelsea · SW3 · Kensington & Chelsea

Rear Extension Drawings in Chelsea SW3

Fixed-fee, MCIAT-chartered rear extension drawings for Chelsea (SW3) homeowners — Royal Borough of Kensington and Chelsea validation and local constraints handled from the start.

Chelsea (SW3) stretches from the King's Road down to the Chelsea Embankment — Georgian and Victorian townhouses in the Chelsea, Cheyne and Royal Hospital conservation areas, a great many of them listed, alongside period mansion blocks. Work concentrates on rear-return extensions, full internal reconfiguration and basement schemes rather than alterations to the protected street frontage.

With so much of SW3 both listed and conservation-controlled, we produce measured drawings and heritage justification to the Royal Borough of Kensington and Chelsea's standard, handling listed-building consent and the borough's tight limits on basement depth, rear returns and construction impact so schemes stay approvable.

Proposed floor plan

Chelsea SW3

Chelsea (SW3) — planning at a glance

Council: Royal Borough of Kensington and Chelsea
Postcode district: SW3
Planning portal: View the Kensington & Chelsea planning portal
Housing stock: SW3 runs from the King's Road to the river across the Chelsea, Cheyne and Royal Hospital conservation areas — fine Georgian and early-Victorian townhouses, many listed, interspersed with red-brick mansion flats. Most projects are rear-return and closet-wing extensions, full internal remodels and basement excavations, since the protected frontages leave little scope for visible street-side change.
Article 4: Royal Borough of Kensington and Chelsea does not publish its Article 4 directions to the national planning register, so permitted development rights in Chelsea (SW3) can’t be confirmed from open data alone — we check the direction schedule with the council before recommending a route, as part of the fixed fee. Conservation-area coverage over the King's Road hinterland and the concentration of listed townhouses strip out most householder permitted development
Conservation: ChelseaCheyneRoyal HospitalHans Town
Sample streets: Cheyne Walk · Royal Hospital Road · Cheyne Row · Cadogan Square
Local constraints: The King's Road hinterland and riverside lie within the Chelsea, Cheyne and Royal Hospital conservation areas, removing most permitted-development rightsA large share of the Georgian and Victorian townhouses are listed, so internal alterations frequently need listed-building consentRBKC's strict basement (subterranean development) policy limits the extent and depth of excavation and controls construction-management impactRear returns and roof alterations are tightly assessed against the grain and party-wall relationships of the historic terraces

Planning in Chelsea (SW3): what to know before you apply

No published householder Article 4 direction applies, but conservation-area designation across SW3 already withdraws most permitted-development rights and listed-building consent is common. RBKC's subterranean development policy generally caps basements at a single storey and imposes strict construction controls.

Typical Chelsea housing stock

SW3 runs from the King's Road to the river across the Chelsea, Cheyne and Royal Hospital conservation areas — fine Georgian and early-Victorian townhouses, many listed, interspersed with red-brick mansion flats. Most projects are rear-return and closet-wing extensions, full internal remodels and basement excavations, since the protected frontages leave little scope for visible street-side change.

Streets we regularly draw for in Chelsea

Cheyne Walk · Royal Hospital Road · Cheyne Row · Cadogan Square

What SW3 is actually built of

Measured from 133 classified residential buildings in SW3, not from a description of the area.

Chelsea SW3 housing mix

Residential building form across the SW3 postcode district, from 133 classified buildings.

Attached on more than one side	86%
Attached on one side	13%
Detached	2%
Median building footprint	71 m²
Addresses per buildingAbove about 2 means flats and maisonettes dominate	2.96
Buildings classified	133

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.

Rear Extension Drawings for Chelsea (SW3) homes: the package and the process

Depth is the number the application turns on, and it has to be measured from the original rear wall of the house rather than from whatever is there now. The drawings carry that dimension, the eaves and ridge heights, the position of any rooflight, and the boundary distances on both sides.

Where the scheme goes beyond the standard allowance and relies on the larger home extension route, the drawings serve a second purpose: they are what the council sends to the neighbours during the consultation. A clear, dimensioned proposed elevation answers the objection about overshadowing before it is made.

Depth is limited by the plot as much as by the rules. A long garden behind a terrace can take the full allowance, while a short one runs out before the rules do — and on a semi or detached house the same depth reads very differently from the boundary.

Do I need planning permission for a rear extension in London?

Many single-storey rear extensions qualify as permitted development, meaning no planning application is needed, provided depth, height and materials stay within set limits. That changes if your property sits in a conservation area or is subject to an Article 4 direction, both of which can remove permitted development rights across a street or borough — in that case a full householder planning application is required regardless of size.

Even where an extension qualifies, most homeowners obtain a Lawful Development Certificate to confirm that status in writing before building — useful for mortgage lenders, buyers and Building Control. We check your property against your borough's constraints before recommending a route.

How deep can a single-storey rear extension go?

Depth is the main constraint on a rear extension, and it depends on your house type and whether you use standard permitted development or the larger home extension scheme.

Permitted development

Standard permitted development allows a single-storey rear extension up to 3 metres deep for terraced and semi-detached houses, or 4 metres for detached houses, generally with eaves height limited to match or stay close to the existing house.

Larger home extension scheme

The prior-approval scheme extends this to 6 metres for terraced and semi-detached houses and 8 metres for detached houses. Your council writes to affected neighbours; if none object within the notification period, approval follows without a full planning application. If an objection is raised, the council assesses the impact on neighbouring light and outlook itself, rather than automatically refusing, so a well-considered design still has a good chance of approval.

Designing the kitchen-diner: rooflights, bi-folds and daylight

Most rear extensions exist to create one open-plan kitchen, dining and living space, so the drawing work focuses on getting light and flow right within the depth you are allowed.

Structural opening sized for bi-fold or sliding doors across most of the rear elevation
Rooflights or a roof lantern positioned to light the centre of the room, away from the shadow line of the main house
Open-plan layout tested against the 45-degree rule, which protects daylight to your neighbours' windows and can limit how close a flank wall or roof comes to the boundary
Floor build-up and threshold detail coordinated so the new floor meets the existing one without a step

Rear extension routes at a glance
Route	When it applies	Typical fee
Permitted development (Lawful Development Certificate)	Depth within 3m (terraced/semi) or 4m (detached), height and materials within PD limits	PD/LDC pack ~£950–£1,450
Larger home extension (prior approval)	Depth up to 6m (terraced/semi) or 8m (detached), with neighbour notification	from £1,100
Full householder planning permission	Extension exceeds PD/larger-home limits, or the property is in a conservation area with an Article 4 direction	Full Planning pack ~£1,600–£2,400
Planning + Building Regulations (structural)	Combined planning and construction-ready pack with structural calculations for the opening and roof	Planning + Building Regs pack ~£2,200–£3,850

Sheet from a rear extension drawings package drawn for a Chelsea property in SW3, showing the existing and proposed arrangement at scale — A sheet from the rear extension drawings package we submit to Royal Borough of Kensington and Chelsea for Chelsea (SW3) properties.

Also in Chelsea SW3

Planning Permission Planning Drawings Architectural Drawings Building Regulations Drawings Loft Conversion Drawings Rear Extension Drawings across Kensington & Chelsea Rear Extension Drawings across London

FAQ

Rear Extension Drawings in Chelsea SW3 — FAQs

How much does a rear extension cost to design in London?+

Rear extension drawings start from £1,100, with the final fee set by the route your extension takes — permitted development, prior approval or full planning — and whether you need building regulations and structural calculations bundled in. The fee is fixed and agreed upfront.

Do I need an architect for a rear extension?+

No. DrawingsDirect is an MCIAT-chartered architectural technologist practice, producing the same council-accepted drawings as an architect for a fixed fee typically around 30% lower.

How long does it take to get rear extension drawings?+

Drawings are typically ready around 7 days from survey. Once submitted, councils have a statutory 8-week period to determine a standard householder planning application.

What is the 45-degree rule?+

It is a daylight test many London councils apply to check that a rear extension does not block too much light to a neighbour's nearest window, measured as a line drawn at 45 degrees from that window. We check it before submission, not after a refusal.

Will I need a Party Wall Agreement for a rear extension?+

Only if your foundations or new walls sit on or near the boundary with a neighbouring property. A straightforward rear extension set within your own plot often does not trigger the Party Wall etc. Act 1996, unlike a Side Return or Wraparound extension, which usually does.

Do I need planning permission for works in Kensington & Chelsea?+

Almost always. Near-comprehensive conservation-area coverage and a high density of listed buildings mean a full planning application — and often listed-building consent — is usually required even for modest works. Permitted development can rarely be assumed here. We confirm the exact designations and listing status for your address before any design begins.

Can I build a basement in Kensington & Chelsea?+

Within limits. The borough's basements policy is nationally known for restricting new basements — generally to a single storey — and controlling excavation extent, alongside a basement impact assessment. A basement can still be viable, but it must be designed to the policy from the outset. We confirm what your site allows and evidence the scheme accordingly.

My home is listed — what consent do I need?+

Listed-building consent is usually required alongside or instead of planning permission, and internal as well as external changes can be controlled. Given the borough's extensive listed-building coverage across Kensington, Chelsea and the mews, we screen listing status first and prepare the heritage-led drawings and justification the council expects.

How long does the Royal Borough take to decide?+

The council determines most householder applications within the statutory eight-week period once validated, though listed-building, basement and conservation cases frequently attract additional consultation. We prepare submissions to the borough's exacting validation and design standards to avoid the drawing queries that cause most delays.

How much do planning drawings cost in Kensington & Chelsea?+

We agree a fixed fee before starting, typically around 30% below an architect's fee for the same council-accepted drawings, with free redraws until the council approves. Heritage-led and listed-building schemes require more evidence than a standard extension, so we quote once we understand your address and scheme rather than by the hour.

Free Fixed Quote

Get your free Chelsea planning assessment

Tell us your Chelsea (SW3) address and ambition — we'll confirm feasibility, local constraints and a fixed fee within one working day.