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Free 2026 London Planning Report — Rear Extension Drawings in Barnes SW13

Open-plan kitchen extension in a Barnes SW13 Victorian village house near the Thames, London Borough of Richmond
Barnes · SW13 · Richmond

Rear Extension Drawings in Barnes SW13

Fixed-fee, MCIAT-chartered rear extension drawings for Barnes (SW13) homeowners — London Borough of Richmond upon Thames validation and local constraints handled from the start.

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Barnes (SW13) is an unusually intact riverside village in Richmond, and it is heavily conservation-controlled: four conservation areas — Barnes Common, Barnes Green, Castelnau and Madrid Road — cover most of the housing. Whether a property sits inside one of those boundaries, and often it does, is the single biggest factor in how an extension, loft or elevation change is designed and assessed.

The Thames wraps the neighbourhood on two sides, so riverside houses along Lonsdale Road and the Terrace also carry flood-zone considerations, and Barnes Common is protected metropolitan open land. We map a Barnes property against the conservation, flood-zone and open-land boundaries first, then design the drawings to Richmond's residential and conservation guidance so the application is validated without a query.

Open-plan kitchen extension in a Barnes SW13 Victorian village house near the Thames, London Borough of Richmond
Isometric illustration of a Barnes SW13 home rear extension drawings design
Proposed floor plan
Barnes SW13

Planning in Barnes (SW13): what to know before you apply

SW13 has no householder Article 4 direction, but its four conservation areas mean permitted development cannot be assumed across most of Barnes, and riverside properties along Lonsdale Road sit within the Thames flood zone — both are checked before we recommend a route.

Typical Barnes housing stock

Victorian and Edwardian terraces and cottages around Barnes Green and the village, the grand Italianate semi-detached villas along Castelnau toward Hammersmith Bridge, and riverside houses fronting the Thames on Lonsdale Road.

Streets we regularly draw for in Barnes

Church Road · Castelnau · White Hart Lane · Lonsdale Road

Rear Extension Drawings for Barnes (SW13) homes: the package and the process

Every rear extension drawings we prepare for an Barnes property is drawn to London Borough of Richmond upon Thames’s validation standards and tuned to the SW13 constraints above. Here is what the drawing package covers and how the process runs from first survey to approval.

A single-storey rear extension is the most common way London homeowners add space, usually taking the form of an open-plan kitchen-diner that opens onto the garden through bi-fold or sliding doors, with rooflights or a roof lantern bringing daylight deep into the plan. Because depth and height are tightly controlled by permitted development rules and by the 45-degree rule that protects neighbouring windows, the design work sits as much in checking what the council will allow as in drawing what you want.

DrawingsDirect draws rear extensions for permitted development, the larger home extension prior-approval scheme and full householder planning, with structural calculations for the opening and roof produced in-house by our MCIAT-chartered team. If your project also involves widening the kitchen sideways or adding a second storey, see our Side Return, Wraparound and Double Storey Extension pages — many London rear extensions grow into one of those during design.

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.

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

Also in Barnes SW13

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FAQ

Rear Extension Drawings in Barnes SW13 — 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 an extension in Richmond?+
More often than in most boroughs, yes. Richmond has some of the most extensive Article 4 coverage in London, so permitted development cannot be assumed even for modest works — many conservation areas such as Richmond Green, Teddington and Kew Green require a full application. We confirm the exact designation for your address first and design accordingly rather than relying on permitted development.
My Richmond home is near the river — does flood risk affect my application?+
It can. Much of the borough lies within the Thames flood zone, and the council expects flood-risk considerations to be addressed for works near the river in Twickenham, Richmond and Hampton. We evidence flood-risk and finished-floor-level considerations within the application so the council can validate and approve without repeated revisions.
What does Richmond's Article 4 coverage mean in practice?+
Article 4 directions remove permitted development rights across many of Richmond's conservation areas, so alterations that would be automatic elsewhere — dormers, cladding, some rear works — need a full householder application here. We design context-led drawings that respond to the borough's period townscape and river frontage, which is what carries an application to consent in Richmond.
How long does Richmond Council take to decide?+
Richmond determines most householder applications within the statutory eight-week period once validated, though conservation and riverside cases can attract additional consultation. Because so much turns on design detail here, we prepare submissions to the validation checklist with the elevations and materials the council expects, to avoid drawing queries.
How much do planning drawings cost in Richmond?+
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 Richmond approves. Conservation and flood-zone cases require more evidence than a standard extension, so we quote once we understand your address and scheme rather than by the hour.
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