An extension in Epsom is judged against the council's own depth limits, its daylight angles and its validation list, so the design has to answer those documents before it answers the wish list. We appoint the structural engineer, build to the calculations, and coordinate the building control application and every inspection stage. Epsom and Ewell's published guidance is specific enough to be worth reading before a drawing is started.
Epsom and Ewell publishes the depths and the angles
3.25 metres is the number to start from. The council's Householder Applications Design Guidance sets that as the maximum projection for a two storey rear extension onto a semi detached two storey house. It also asks that the extension stay outside a 45 degree plan angle taken from the edge of the neighbours' windows.
There is a second angle to design against. The guidance asks rear extensions to comply with a 43 degree daylight angle along the side and rear plot boundaries, measured from a point 2.5 metres above ground level. A depth and two angles is a tight envelope, and it is easier to design inside it from the start than to argue with it later. We build what has consent, so we would rather the consent was won at the first attempt.
Building up to the boundary, and the assessment for anything above ground floor
A wall on the boundary has rules of its own. Where a rear extension is taken up to the plot boundary, Epsom and Ewell's householder guidance says that wall should have no windows and should be no higher than 2.5 metres. For terraced properties the guidance adds an exception where the wall backs onto an existing extension's party wall.
Anything above ground floor triggers an assessment. The council requires a Daylight and Sunlight Assessment for any above ground floor extension. It has to show a 45 degree line drawn from the corners of the proposed extension to the centre of the nearest habitable window on the rear elevation of both adjoining properties. That is a validation requirement, so it is not something to supply later if somebody asks for it.
What the foundations will be going into
It depends which part of Epsom you are in. Above the Lambeth Group at Epsom town centre and Chalk Lane, the British Geological Survey maps a superficial layer of undifferentiated River Terrace Deposits, recorded as sand and gravel. At Horton Lane and Noble Park no superficial deposits are mapped over the London Clay, so the clay bedrock is the mapped ground there. The council's Hospital Cluster appraisal records the soil beneath the former Horton, Long Grove, The Manor, St Ebba's and West Park sites as London Clay mixed with medium clay loams. Those soils can waterlog in winter and dry out in summer.
Digging in Epsom can raise a second question. Applicants seeking planning permission within an area of high archaeological potential are required to undertake a prior assessment of the possible archaeological significance of the site, and may be required to submit a desk based assessment with the application. That is worth establishing at the address, because it affects when you can start rather than only what you can build.
On the Downs Road Estate, a porch needs permission
The Article 4(2) direction there is unusually wide. It brings under planning control all front extensions of whatever size, including porches, changes to roof materials and new rooflights on front facing roof slopes. It also covers changes to the tile hanging on front and street facing flank elevations, replacement front and garage doors, new hardstandings, and front walls, gates or other enclosures. Applications submitted under an Article 4(2) direction in Epsom and Ewell are free of charge. Three of the borough's heritage Article 4 directions sit on 20th century residential estates rather than historic cores: the Downs Road Estate, Ewell Downs Road and The Green, and Higher Green.
Trees govern the footprint there. The estate layout was designed around existing stands of trees, including a row along Downs Road planted by Lord Rosebery at the end of the 19th century, which forms a double row in places and was deliberately retained. Where works are likely to affect mature trees on or next to the site, the council requires an Arboricultural Impact Assessment prepared by a qualified arboriculturist in accordance with BS 5837:2012. It names root severance from excavations for foundation construction as a harmful encroachment.
- Flat and pitched roofs with rooflights or lanterns
- Bi-fold, sliding and French door openings to the garden
- Drainage diversion and build-over agreements with the water authority
- Full fit-out, finishing and making good
- Planning applications and permitted development assessments
The GS Renovation Difference in Epsom
Extensions in Epsom are measured against numbers the council has published, so we design and build to them rather than around them. We appoint the structural engineer, build to the calculations, and coordinate the building control application and every inspection stage. Abdelaaziz Saaid is your single point of contact from the first survey to the completion certificate. Fully insured, with free quotations that carry no obligation.
- Brick and mortar matched to the existing elevation
- Permitted development checked before you pay for a planning application
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- One point of contact on the phone, not a call centre
- Drainage diverted or built over with the right approval in place
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