Rear extension in Havering
Do you need planning permission for a rear extension in Havering?
Outside the conservation areas and Green Belt, much of Havering's suburban semi-detached stock keeps permitted development rights for a single-storey rear extension within the limits, or larger via prior approval. Inside a conservation area, expect a full application. The two small-HMO conversion directions (in force since 13 July 2016) together cover the whole borough but do not themselves remove ordinary rear-extension rights.
Hornchurch, Upminster and Romford semis extend under PD; Gidea Park, the village conservation areas and Green Belt need a full application.
Havering is where suburbia meets the countryside — from Romford and Hornchurch out to Green Belt villages and the Thames-side at Rainham. Generous plots make rear extensions a staple outside protected streets. Conservation set pieces such as the model garden suburb at Gidea Park add design scrutiny where designation applies.
What actually applies in Havering
Conservation areas in Havering
Real · planning.data.gov.ukEvery designated conservation area in Havering from the official dataset — inside one, permitted development narrows and design scrutiny rises.
- Corbets Tey
- Cranham
- Gidea Park
- Havering-atte-Bower
- Langtons, Hornchurch
- North Ockendon
- RAF Hornchurch
- Rainham
- Romford
- St Andrew's Church, Hornchurch
- St Leonard's, Hornchurch
Source: planning.data.gov.uk · Open Government Licence. Boundaries are checked at address level by the area report.
Article 4 directions in Havering
Real · planning.data.gov.ukNo Article 4 geometry for Havering appears in the national planning.data.gov.uk dataset, but the borough controls HMO conversions through two Article 4 directions in force since 13 July 2016 that together cover the whole borough (one for Brooklands, Romford Town, Heaton and Gooshays; a second for the rest), removing the right to convert a house to a small HMO. Much of the borough is Green Belt. Check the council's Article 4 pages for the position at a specific address.
Source: planning.data.gov.uk · Open Government Licence. 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 Havering, 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 Havering?
| 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 Havering
National geometry does not currently hold Havering's Article 4 directions — confirm HMO positions on the council's pages. Green Belt designation in the rural edge can limit disproportionate additions.
Postcode districts in Havering
RM1 is Romford — the historic market-town core and conservation area at the borough's centre.
RM1 — Romford →RM2 is Gidea Park — a celebrated model garden suburb and 1911 exhibition estate, protected as a conservation area with close design control over its Arts and Crafts houses.
RM2 — Gidea Park →RM11 covers Hornchurch and the leafy Emerson Park — the Langtons and St Andrew's Church conservation areas among them.
RM11 — Hornchurch & Emerson Park →RM14 is Upminster and Cranham on the rural edge — the Cranham conservation area and North Ockendon, with Green Belt beyond.
RM14 — Upminster & Cranham →RM13 covers Rainham and South Hornchurch — the Rainham conservation area around Rainham Hall, near the Thames-side marshes.
RM13 — Rainham & South Hornchurch →RM3 covers Harold Hill and Harold Wood in Havering — mid-century and suburban stock on larger plots.
RM3 — Harold Hill & Harold Wood →RM5 is Collier Row and Chase Cross, spanning Havering with a Barking and Dagenham edge.
RM5 — Collier Row & Chase Cross →RM7 covers western Romford and Rush Green in Havering (with a Barking and Dagenham edge).
RM7 — Romford west & Rush Green →RM12 is Hornchurch and Elm Park — interwar Havering stock with deep rear gardens.
RM12 — Hornchurch & Elm Park →Rear extension in Havering, asked straight
Do I need planning permission for a rear extension in Havering?
How much does a rear extension cost in Havering?
Do the July 2016 small-HMO conversion directions affect rear extensions?
Is Green Belt a problem for rear extensions?
Do I need a party wall agreement?
What applies at your address?
Borough-level rules only narrow it down. Enter a Havering 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 Havering 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.