House
extensions
in Oxshott, KT22
Designers, Architects, Engineers & Builders Under One Roof.
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Extending an Oxshott house can mean working with a large plot, mature trees and, near the edge of the village, the Green Belt. We pin down which consent route applies to the address before a line is drawn.
A detached Oxshott house on a generous plot can look as though it has room to grow. The limits sit around the house rather than in it: the trees that screen it, the neighbouring windows, the fall of the garden and, for houses at the edge of the village, the Green Belt line. We design an extension here from a survey of the whole plot, not only the back wall.
Where a house has been extended before, we work out what was original first. Green Belt policy and the permitted development limits both take the original house as their yardstick, so an earlier addition can use up room that a new design might otherwise have.
Green Belt or not: the first question for an Oxshott extension
The Design Code shows Green Belt land surrounding the village, and the Core Strategy describes broad areas of it around the whole settlement area. A house at the edge of Oxshott may therefore sit inside the boundary, and that changes the test an extension has to meet.
Within the Green Belt, Development Management Plan policy DM18 is the council's yardstick, and it measures an extension against the house's size on 1 July 1948, or its size when first built if that is later. We do not paraphrase the test: it is reproduced word for word on our Elmbridge page, and we pin down the original house from records and the survey before any design work.
The Design Code covers the built-up area and leaves out the defined Green Belt, although its overarching design principles still apply to new development there. Either way, the Code's expectations on form and materials are a sound starting point for an Oxshott extension.
Sources: Elmbridge Borough Council: Elmbridge Design Code 2024 (SPD); Elmbridge Borough Council: Elmbridge Core Strategy; Elmbridge Borough Council: Development Management Plan (April 2015)
Permitted development for a detached Oxshott house
Class A of Part 1 of the General Permitted Development Order allows the enlargement of a dwellinghouse without a planning application, within limits. On a detached house, a single-storey rear addition can reach as far as 4 metres beyond the original rear wall; on any other house, 3 metres.
A deeper single-storey addition at the back, reaching 8 metres on a detached house, is open only to houses that are neither on article 2(3) land nor on a site of special scientific interest. Paragraph A.4 then attaches its own conditions: before building starts, the council must receive, among other things, a written description, a site plan and the addresses of any adjoining premises.
Article 2(3) land takes in conservation areas. None of the five the Core Strategy lists for the settlement area is named after Oxshott, but we confirm the position for each address before relying on the larger limits. The national rules are set out on our Surrey page.
Permitted development does not override tree protection. According to the council, a scheme that would otherwise be permitted still needs permission if it could affect a protected tree, roots included; and protection can come from a preservation order, a planning condition or ancient woodland status, not only from a conservation area.
Sources: legislation.gov.uk (The National Archives): The Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 1 (development within the curtilage of a dwellinghouse) - latest available (revised); legislation.gov.uk (The National Archives): GPDO 2015, Schedule 1, Part 1 - Article 2(3) land; Elmbridge Borough Council: Elmbridge Core Strategy; Elmbridge Borough Council: Building near a tree; Elmbridge Borough Council: Protected trees
What the Design Code asks of an Oxshott extension
A householder application now includes a Design Code Checklist. The Code wants the proposed plot ratio stated alongside the ratio for each adjoining plot, and expects householder extensions to keep inside its indicative range where possible. Where plot sizes vary along a street, that comparison is part of our survey.
On form, the Code wants an extension's roof to echo the scale, design and angle of the existing roof, and it advises against giving a pitched-roof house a flat-roofed addition, with a possible exception for single-storey rear additions to a house of two or more storeys. A two-storey addition should carry the house's eaves line through without rising above it, and its materials and detailing should follow the original in design, colour and texture.
Two of the Code's points are especially relevant on large plots. Anything built above ground floor should leave a gap of 1 metre or more to the boundary, and turning a flat roof into a balcony or raised terrace is generally unacceptable unless it is well screened or the plot is large enough to avoid overlooking.
Sources: Elmbridge Borough Council: Design Code SPD page; Elmbridge Borough Council: Elmbridge Design Code 2024 (SPD)
Trees, drainage, party walls and sign-off
Building near trees means meeting BS 5837:2012, and the council's guidance applies to trees on adjoining land and in the street as well as on the site. An application may need to show the trees' root protection areas and give existing and proposed finished levels, which on a sloping Oxshott garden we prepare together.
For rainwater from a new roof, the council's April 2024 flood study rates the built-up core of Cobham and Oxshott as likely to take infiltration well. If a soakaway is proposed, the study expects groundwater evidence showing a 1m unsaturated zone between the soakaway's base and the highest recorded groundwater level.
Being detached does not always rule out party wall work. Notice to the neighbour is required before you build on or right up to the shared boundary, or excavate below and close to their foundations, and a garden wall on the line can count as a party wall even though a timber fence does not.
Building regulations approval for an extension comes from Elmbridge Building Control Services (EBCS), for Elmbridge Borough Council, until 31 March 2027, and from 1 April 2027 the provider named by East Surrey Council, or from a registered building control approver if you prefer one.
Sources: Elmbridge Borough Council: Building near a tree; Elmbridge Borough Council: Level 1 Strategic Flood Risk Assessment, April 2024 (AECOM); GOV.UK: Party walls and building work (printable guide); Elmbridge Borough Council: Building control; Surrey councils (Future Surrey hub, linked from Elmbridge home page): East Surrey Council (Future Surrey LGR hub); GOV.UK: Building regulations approval (printable guide)
From the plot survey to the finished extension
Our first task is a measured survey covering both house and plot: garden levels, where nearby trees stand and how far they spread, drainage runs, and any neighbouring windows that face the work.
Options are sketched against whichever consent route applies, so you can compare what permitted development would allow with what an application might achieve before one is taken forward.
Foundations and any openings into the existing house are engineered by our structural engineer. Close to trees the foundation design follows the arboricultural advice, which can mean a different foundation type rather than a smaller extension.
On site, each opening into the house is weathered and secured as it is made, and the lawn, hedges and verge are protected during the build and made good at the end.
Outside Oxshott, and in London rather than Surrey: Holland Avenue, Wimbledon SW20. That completed project of ours combined a loft conversion, a double-storey extension to the rear and side, and a whole-home refurbishment, as its case study describes.
Sources: Hampstead Renovations: Holland Avenue, Wimbledon SW20 case study
House Extensions in Oxshott: Questions
Could my Oxshott house be in the Green Belt, and what would that mean for the size of an extension?
The Design Code shows Green Belt land surrounding the village, so a house near its edge may be inside it, and we check the boundary for your address. If it is, policy DM18 of the Development Management Plan compares the proposal with the original building, meaning its size on 1 July 1948 or when first built if later, and the test is reproduced word for word on our Elmbridge page. Outside the Green Belt, size is set by permitted development or by an application assessed against the local plan and the Design Code.
Can a rear extension in Oxshott go ahead without a planning application?
It can, if the house still has its permitted development rights and no designation applies. On a detached house, Class A permits a single-storey addition at the back reaching 4 metres beyond the original rear wall, and, on a house outside article 2(3) land and off a site of special scientific interest, one of up to 8 metres under the paragraph A.4 conditions. If the work may affect a protected tree or its roots, permission is still needed.
Would article 2(3) land limit an extension to my Oxshott house?
It can. Article 2(3) land includes conservation areas, and houses on it cannot use the deeper rear extension allowance. None of the conservation areas listed for the Cobham, Oxshott, Stoke D'Abernon and Downside area is named after Oxshott, but we confirm the position for each address on the council's map before relying on the larger limits.
What part does flood risk play in an Oxshott extension?
Most of the village is on high land, roughly 45-75m AOD according to the council's April 2024 flood study, but the River Rythe's functional floodplain includes land south of the A3 at Oxshott. The Environment Agency's planning flood map, searched by address, shows whether a flood risk assessment is required; the Environment Agency says that for simple, low-risk work like a house extension, owners may be able to prepare one without a consultant.
Who signs off an Oxshott extension under the building regulations?
Extending a home appears in the council's list of jobs that can require building control approval. At Oxshott addresses that is Elmbridge Building Control Services (EBCS), for Elmbridge Borough Council, until 31 March 2027, and from 1 April 2027 the provider named by East Surrey Council, or a registered building control approver. We submit extensions as full plans, the most thorough route, and you should receive a completion certificate once the finished work complies.
What should I have ready for an extension feasibility visit in Oxshott?
Any existing plans, earlier planning decisions or building control certificates for the house, a title plan showing the boundaries, and photographs of the rear and side elevations and the trees nearest the likely extension. If the house has been extended before, the drawings for that work help us work out what the original house was.
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