The permitted development rules for rear extensions
On a house, a single-storey rear extension is permitted development if it projects no more than 3 m from the original rear wall on a terraced or semi-detached house, or 4 m on a detached house, is no higher than 4 m, has eaves no higher than 3 m where it comes within 2 m of a boundary, and uses materials similar in appearance to the house. The larger home extension route allows 6 m or 8 m through a 42-day prior approval, where the council consults the neighbours.
Flats and maisonettes have no householder permitted development rights, so any rear extension to a flat needs planning permission. Previous extensions count against the allowance, and the larger home extension route is not available in conservation areas.
What changes in Newham
In a conservation area a single-storey rear extension can still be permitted development within the 3 m or 4 m limit, but cladding it in materials that differ from the house is not, and the 6 m and 8 m prior approval route is closed.
The local constraints that most often decide the route in Newham are listed below, taken from our Newham area page. Each one is a reason to confirm the address on Newham's constraints map before relying on permitted development.
- Borough-wide Article 4 direction on HMOs. Newham has had a borough-wide Article 4 direction since 2013 removing permitted development for changing a house (Class C3) into a small house in multiple occupation (Class C4). Any new HMO needs a planning application as well as a licence under the council's borough-wide licensing scheme. Check the council's planning and licensing pages for the current rules. Source
- Conservation areas and the Woodgrange Estate. Newham has relatively few conservation areas, including the Woodgrange Estate in Forest Gate, Stratford St John's, Three Mills, Sugar House Lane and Durham Road. The Woodgrange Estate also has an Article 4 direction removing permitted development for front alterations, windows, boundary walls and some roof works. Roof extensions are not permitted development in any conservation area. Source
- Thames and Lee flood risk. Much of southern Newham, including Canning Town, Custom House, Beckton, Silvertown and North Woolwich, and land along the River Lee, Channelsea River and Bow Creek in Stratford and West Ham, sits in Flood Zone 3 behind the Thames defences. Ground-floor extensions and any basement there normally need a flood risk assessment. Source
- Listed buildings. Three Mills, Abbey Mills Pumping Station, East Ham Town Hall, St Mary Magdalene in East Ham and All Saints West Ham are among Newham's listed buildings. Listed building consent is needed for almost any alteration, internal or external. Source
What Newham planning officers look for
Newham officers are firm on the pattern of terrace rear elevations and on HMO standards. Common refusal reasons are rear extensions that fail the 45-degree test or exceed the neighbour's depth, full-width box dormers, front dormers, roof extensions in conservation areas and HMOs with undersized rooms or too many in one street. Outside conservation areas a rear dormer within 40 m³ and a 3 m or 6 m rear extension are routinely lawful. The council offers paid pre-application advice and decisions frequently run beyond 8 weeks; allow 10–14 weeks.
Fees and timelines
The council fee for a householder application is £528 and for a Lawful Development Certificate £264 (England, from 1 April 2025; verify before applying). Both are decided within 8 weeks of validation.
Our own fee for the drawings and the application is fixed once quoted and depends on the project type, its size and the constraints above. Answer six questions in the quote tool and we email you an indicative figure within minutes, then a written fixed-fee quote within 24 hours.
