Rear extension in Barking and Dagenham
Do you need planning permission for a rear extension in Barking and Dagenham?
Outside the conservation areas and any upward-extension Article 4 area, much of the borough's suburban stock keeps permitted development rights for a single-storey rear extension within the limits, or larger via prior approval, to the Residential Extensions and Alterations SPD. The borough-wide small-HMO conversion direction does not itself remove ordinary rear-extension rights. Check the address first.
Becontree and Dagenham semis extend under PD; the Barking Abbey and Dagenham Village conservation areas need a full application.
Barking and Dagenham is dominated by the vast interwar Becontree Estate alongside the historic core around Barking Abbey and the Thames-side at Riverside. Rear extensions are everyday projects on unconstrained suburban stock. Separate upward-extension directions in specific areas remove the right to add a storey under permitted development — that is a different product from a single-storey rear extension.
What actually applies in Barking and Dagenham
Conservation areas in Barking and Dagenham
Real · planning.data.gov.ukEvery designated conservation area in Barking and Dagenham from the official dataset — inside one, permitted development narrows and design scrutiny rises.
- Abbey and Barking Town Centre Conservation Area
- Abbey Road and Riverside Conservation Area
- Chadwell Heath Anti-aircraft Gun Site Conservation Area
- Dagenham Village Conservation Area
Source: planning.data.gov.uk · Open Government Licence. Boundaries are checked at address level by the area report.
Article 4 directions in Barking and Dagenham
Real · planning.data.gov.ukBarking and Dagenham's Article 4 directions, partly recorded in the national dataset, include a borough-wide HMO direction (planning permission to convert a house to a small HMO), upward-extension directions in specific areas (recorded as the Dagenham Village and Lymington directions, removing the right to add a storey), and a direction controlling certain commercial-to-residential changes outside industrial land. The Residential Extensions and Alterations SPD sets householder design expectations. Check the council's Article 4 register for the direction that applies at a given address.
Source: planning.data.gov.uk · Open Government Licence · 3 directions recorded. Checked at address level by the area report.
Prices: HM Land Registry UK House Price Index, December 2025 · Open Government Licence.
The planning route — PD or permission?
Permitted development (GPDO Class A) covers single-storey rear extensions up to 3m beyond the original rear wall on attached houses and 4m on detached, with a maximum height of 4m. The 'larger home extension' route extends this to 6m/8m through prior approval with neighbour consultation — but that larger route is not available in conservation areas.
In conservation areas, the basic 3m/4m single-storey rear PD allowance usually survives — what conservation-area status removes is side extensions and two-storey rear extensions. An Article 4 direction can remove more, but Camden's directions in Hampstead and Belsize target front-and-side appearance (solar panels, window changes, boundary treatments), not the single-storey rear allowance. Flats have no PD rights at all. Two-storey rear extensions in conservation areas always need full permission.
Practical rule across London: check the address first. If a conservation area or Article 4 direction applies, budget for a full householder application decided on design, neighbour daylight (the 45-degree test) and materials.
Permitted development limits — rear extension
| Single-storey rear depth — attached house | 3m beyond the original rear wall |
| Single-storey rear depth — detached house | 4m beyond the original rear wall |
| Larger extension via prior approval | 6m attached / 8m detached — not in conservation areas |
| Maximum height (single storey) | 4m |
| Two-storey rear in a conservation area | Full planning permission required |
| Flats | No permitted development rights |
Limits summarise the General Permitted Development Order (Schedule 2, Part 1) as it applies in London. In Barking and Dagenham, a conservation area, Article 4 direction or listed status changes the route — the panels above show what is designated, and the address check confirms what applies at your property.
How much does a rear extension cost in Barking and Dagenham?
| Cost per m² (low — straightforward site) | £3,000 |
| Cost per m² (expected) | £3,800 |
| Cost per m² (high — conservation spec, hard access) | £4,600+ |
| Typical build cost (12–18m² single storey) | £36,000 – £83,000 |
| Professional fees, surveys, party wall (add) | 10–18% of build |
Indicative London ranges calibrated from real project data. Conservation-area specifications (matching stock brick, lime mortar, bespoke glazing) and restricted rear access are the two biggest cost drivers. VAT not included.
Realistic timeline
| Design and drawings | 4–8 weeks |
| Planning decision (full application) | 8–12 weeks (8-week statutory target) |
| Prior approval route, where available | 42 days |
| Party wall agreements | 4–10 weeks (parallel) |
| Build | 3–5 months |
What catches people out in Barking and Dagenham
Confusing a single-storey rear with an upward extension under local directions is the planning trap. Confirm conservation, HMO and upward-extension positions at the address.
Postcode districts in Barking and Dagenham
IG11 is Barking — the Abbey and Barking Town Centre and Abbey Road and Riverside conservation areas around the abbey ruins.
IG11 — Barking →RM8 sits in the vast interwar Becontree Estate — one of the largest council-built estates in the world.
RM8 — Becontree & Dagenham →RM9 covers Becontree Heath and the Valence area of Dagenham, still dominated by the interwar estate.
RM9 — Becontree Heath & Dagenham →RM10 includes the Dagenham Village conservation area around the parish church — which carries an Article 4 direction removing the permitted development right to add a storey.
RM10 — Dagenham Village →Rear extension in Barking and Dagenham, asked straight
Do I need planning permission for a rear extension in Barking and Dagenham?
How much does a rear extension cost in Barking and Dagenham?
Does the small-HMO conversion direction affect rear extensions?
Does an upward-extension direction stop a single-storey rear?
Do I need a party wall agreement?
What applies at your address?
Borough-level rules only narrow it down. Enter a Barking and Dagenham postcode for the live constraint check — conservation area, Article 4 and sold-price comparables, cited to source.
Need it in writing for one address? A planning permission report for a Barking and Dagenham property — from £59, or surveyor-reviewed from £295.
Planning Permission Checker provides planning and cost intelligence for early feasibility only. It is not legal, planning, valuation, architectural, structural, or surveying advice. All estimates are indicative and must be verified by qualified professionals before purchase, design, planning submission, or construction.
Cost estimates are indicative only — not a quotation. Final price depends on survey, specification, structure, access, party wall matters, VAT, professional fees, and contractor availability.
Planning outcomes are not guaranteed. Local planning authorities make final decisions.