House Extensions Epsom

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.

For Epsom, on London-derived ranges a single-storey rear extension typically starts from £40,000, or £2,000 to £2,800 per m²; Surrey work generally runs below that. GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Epsom: the structural engineer we appoint designs the structure, we build it, and building control signs it off.

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 single storey rear extension onto a semi detached or terraced house, and the same 3.25 metres 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. For a kitchen extension that depth is the whole brief: the units, any island and the beam back into the original house are drawn to 3.25 metres from the first sketch, not cut back after a planning officer reads the guidance out. The guidance applies across the borough, so a rear extension in Ewell is held to the same figures as one in Epsom.

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.

Housing in Epsom

The valuation list shows roughly 16,290 homes in Epsom, of which 15% are pre-1919, 23% interwar and 60% post-1945, split 35% flats to 65% houses. 22% of homes here are semi-detached; a rear extension on a semi in Epsom digs beside the attached neighbour, so one party wall notice is usual.

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. The council has stated that applications needed only because of an Article 4(2) direction are free of charge, though the current fee is worth confirming with the council before submitting. 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.

Kitchen extensions in Epsom

65% of the houses in Epsom are semi-detached or detached, which usually leaves room for a kitchen extension across the full rear width, with a steel beam over the opening into the house. The fit-out is priced on its own page, kitchen renovation in Epsom; the build figures are in the table above.

Side return extensions in Epsom

Side returns belong to Victorian and Edwardian terraces, and only 15% of homes in Epsom predate 1919, so they are the exception here; most extensions run across the full rear width instead. Our side return extension page covers the build in detail, with build rates of £2,400 to £3,200 per m².

Double storey extensions in Epsom

Under permitted development a two-storey rear extension can go no more than 3 metres beyond the original rear wall and must stay at least 7 metres from the rear boundary, and in a conservation area it is not permitted development at all. Many gardens are too short for the 7 metre rule, so a double storey extension in Epsom often needs planning permission from Epsom and Ewell Borough Council. With 42% of homes here semi-detached or detached, the side of the house is often an option too. Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.

• 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

VOA Council Tax stock of properties, March 2025, for Epsom Town, Epsom North, Epsom Downs & Common and Horton & Manor Park. Counts rounded by the VOA.

If you are weighing up house extensions in Epsom, it may help to read RSJ and steel beam installation in Epsom, house extensions in Leatherhead, double storey extensions, party walls and extensions, house extensions across London and Permitted Development Rights.

The GS Renovation Difference in Epsom

Extensions in Epsom are measured against numbers the council has published, so the drawings are prepared to them and we 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.

• Permitted development checked before you pay for a planning application
• Rated 4.9 from 31 reviews on MyBuilder
• Drainage diverted or built over with the right approval in place

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.