Single-storey rear extension onto a garden behind an interwar Becontree RM9 LCC cottage in Barking and Dagenham

Becontree · RM9 · Barking & Dagenham

Rear Extension Drawings in Becontree RM9

Fixed-fee, MCIAT-chartered rear extension drawings for Becontree (RM9) homeowners — London Borough of Barking and Dagenham validation and local constraints handled from the start.

Becontree (RM9) is defined by one thing above all: the Becontree Estate, built by the London County Council between 1921 and 1935 and still one of the largest public housing estates ever created, with roughly 26,000 homes laid out on garden-suburb principles. Almost every householder project here is an extension or loft on one of those cohesive interwar two-storey cottages, so the drawings have to sit comfortably within a very consistent, planned streetscape.

There is no conservation area covering Becontree — that is a genuine, verified fact, not an omission. Its planning character is instead shaped by the sheer uniformity of the estate layout and by the London Borough of Barking and Dagenham's design expectations, which lean on keeping the original cottage rhythm, materials and building lines intact. We treat that estate cohesion, rather than a conservation designation, as the reference point when we design an extension.

Because so many Becontree houses passed into private ownership after Right to Buy, demand for rear extensions, side infills and loft conversions is steady across streets like Gale Street, Lodge Avenue and Fitzstephen Road. We check each property's permitted-development position against Barking and Dagenham's borough-wide controls first, then prepare drawings that either stay within permitted development or are ready to validate as a full householder application.

Proposed floor plan

Becontree RM9

Becontree (RM9) — planning at a glance

Council: London Borough of Barking and Dagenham
Postcode district: RM9
Planning portal: View the Barking & Dagenham planning portal
Housing stock: Two-storey interwar cottages — short terraced and semi-detached runs of brick and rendered houses set behind small front gardens on wide, uniformly planned streets. Built by the London County Council between 1921 and 1935, many are now privately owned following Right to Buy, which is what drives the steady flow of rear-extension and loft-conversion work across the estate.
Article 4: No area-specific Article 4 direction is published for the Becontree Estate; Barking and Dagenham's borough-wide permitted-development controls and the council's householder design guidance still apply.
Sample streets: Lodge Avenue · Gale Street · Marlborough Road · Fitzstephen Road · Ilchester Road · Rutland Gardens · Babington Road · Dronfield Gardens · Hewett Road · Cornworthy Road · Harrold Road · Easebourne Road
Local constraints: Strong estate-wide visual cohesion: the uniform interwar cottage layout means front-elevation changes, roof forms and materials are assessed against a consistent street rhythm rather than a one-off houseBarking and Dagenham's borough-wide permitted-development limits and householder design guidance govern extension depth, height and coverage — no local Article 4 direction narrows them further on the estateMatching original facing brick, render finishes and roof tiles so a rear or side addition reads as part of the original cottage rather than an obvious bolt-onModest original plot and garden sizes on many terraced runs, which constrain how deep a single-storey rear extension can go before it needs a full householder applicationSemi-detached and short-terrace forms where side and rear building lines are shared with neighbours, making party-wall relationships and overshadowing relevant to what gets approved

Planning in Becontree (RM9): what to know before you apply

Because the estate is so uniform, Barking and Dagenham assess extensions on Becontree cottages against the consistent interwar street pattern, so matching original brick, render and roof form matters more than on a mixed-typology road. There is no conservation area and no estate-specific Article 4 direction, so many houses retain permitted development rights for rear and loft work — but the modest original plots and shared building lines mean depth, height and neighbour impact are the points a householder application is judged on.

Typical Becontree housing stock

Two-storey interwar cottages — short terraced and semi-detached runs of brick and rendered houses set behind small front gardens on wide, uniformly planned streets. Built by the London County Council between 1921 and 1935, many are now privately owned following Right to Buy, which is what drives the steady flow of rear-extension and loft-conversion work across the estate.

Streets we regularly draw for in Becontree

Lodge Avenue · Gale Street · Marlborough Road · Fitzstephen Road · Ilchester Road · Rutland Gardens · Babington Road · Dronfield Gardens · Hewett Road · Cornworthy Road · Harrold Road · Easebourne Road

What RM9 is actually built of

Measured from 248 classified residential buildings in RM9, not from a description of the area.

Becontree RM9 housing mix

Residential building form across the RM9 postcode district, from 248 classified buildings.

Attached on more than one side	62%
Attached on one side	37%
Detached	1%
Median building footprint	48 m²
Addresses per buildingAbove about 2 means flats and maisonettes dominate	1.06
Buildings classified	248

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 Becontree (RM9) 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 Becontree property in RM9, showing the existing and proposed arrangement at scale — A sheet from the rear extension drawings package we submit to London Borough of Barking and Dagenham for Becontree (RM9) properties.

Also in Becontree RM9

Planning Permission Planning Drawings Architectural Drawings Building Regulations Drawings Loft Conversion Drawings Rear Extension Drawings across Barking & Dagenham Rear Extension Drawings across London

FAQ

Rear Extension Drawings in Becontree RM9 — 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 to extend a house on the Becontree Estate?+

Not always. Many Becontree cottages retain permitted development rights, so a modest single-storey rear extension or a rear loft conversion can often proceed without a full planning application. Because the original plots are compact and the estate is uniform, we check your property's size limits and building lines against Barking and Dagenham's controls first, and prepare a full householder application where the project goes beyond permitted development.

Is Becontree in a conservation area?+

No. There is no conservation area covering the Becontree Estate. Its planning character is shaped instead by the estate's uniform interwar cottage layout and Barking and Dagenham's householder design expectations, which favour keeping the original street rhythm, materials and roof form intact when you extend.

How much do planning and building-regulation drawings cost for a Becontree extension?+

We work to fixed fees agreed before we start, with a typical turnaround of around seven days for a standard rear extension or loft on a Becontree cottage. As a chartered architectural technologist practice we produce the same council-accepted planning and building-regulation drawings as an architect, usually for a lower fee, and include free redraws until your application is approved.

How long does Barking & Dagenham Council take to decide?+

The council determines most householder applications within the statutory eight-week period once validated; conservation cases can attract additional consultation. The commonest delay is a validation query, so we prepare submissions to the council's checklist with correctly scaled existing and proposed drawings and a location plan.

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