The permitted development rules for side extensions
A single-storey side extension is permitted development on a house if it is no wider than half the width of the original house, no higher than 4 m, with eaves no higher than 3 m where it comes within 2 m of a boundary, and finished in materials similar in appearance to the house.
Anything wider than half the original house, any two-storey side extension, and any side extension on a flat needs planning permission. Garage conversions that keep the walls are usually permitted development; extending beyond them is assessed as a side extension.
What changes in Havering
Side extensions are not permitted development in a conservation area at all, so there a planning application is always required.
The local constraints that most often decide the route in Havering are listed below, taken from our Havering area page. Each one is a reason to confirm the address on Havering's constraints map before relying on permitted development.
- Green Belt. Around half of Havering is Green Belt, covering Havering-atte-Bower, Noak Hill, Harold Hill's northern edge, North Ockendon, Cranham's fringes and the Rainham and Wennington marshes. Extensions to houses in the Green Belt must not be disproportionate to the original dwelling, and outbuildings face a strict test. Source
- Gidea Park Article 4 direction. The Gidea Park garden suburb conservation area has a long-standing Article 4 direction removing permitted development for extensions, roof alterations, windows, porches, boundary walls and hard standings. Almost any external change there needs a planning application. Check the council's constraints map for the exact boundary. Source
- Conservation areas. Havering's conservation areas include Gidea Park, Havering-atte-Bower, Cranham, Corbets Tey, Rainham Village, North Ockendon, St Andrew's Hornchurch and Langtons. Roof extensions are not permitted development inside them and extensions are expected to be subordinate and in matching materials. Source
- Thames and river flood risk. Rainham, Wennington, South Hornchurch and the Beam Park area sit in tidal Flood Zone 3 behind the Thames defences, and the Rivers Rom, Ingrebourne and Beam put parts of Romford, Hornchurch, Harold Wood and Elm Park in Flood Zones 2 and 3. Ground-floor extensions there may need a flood risk statement. Source
- Listed buildings. Rainham Hall, Upminster Tithe Barn and windmill, Langtons and the village cores of Havering-atte-Bower and North Ockendon contain listed buildings. Listed building consent is needed for almost any alteration. Source
What Havering planning officers look for
Havering officers are, in our experience, pragmatic on suburban householder work but firm on set-backs, the 45-degree test and plot coverage in Emerson Park and Gidea Park. Common refusal reasons are two-storey side extensions flush with the front wall, rear extensions deeper than the neighbour's, front dormers, and outbuildings in the Green Belt. Hip-to-gable lofts and 4–6 m rear extensions on ordinary 1930s semis are usually accepted. The council offers paid pre-application advice and decisions often run beyond 8 weeks, so 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.
