House
extensions
in Claygate, KT10
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Rear, side and wrap-around extensions for Claygate houses, sized to the plot and the gaps between neighbours, with the planning route settled before the design is fixed.
An extension in Claygate is largely a question of the space around the house: how much garden remains, how close the new wall comes to the boundary, and how the new roof meets the old one. We draw the existing house and its whole plot first, with the neighbours' windows and the trees, because they shape the design as much as the floor area does.
The planning route follows from that survey. Some extensions can go ahead as permitted development and others need a householder application, and a conservation area or a Green Belt plot changes the starting point, so we confirm which applies to the address before the design goes far.
Extending a Claygate house without closing the gaps
Elmbridge's 2012 character assessment counts the space between and around houses as a significant part of Claygate's built character, and its advice on replacement houses asks for sensible separation distances that avoid a terracing effect. Among the issues raised for the Foley Road area were poor house extensions that often double the size of the existing house. That assessment now serves as a description: for applications submitted after 6 January 2025 the Design Code, adopted on 17 April 2024, replaced the Design and Character SPD and its companion guides.
That shapes a side extension above all. Before testing floor area we test a set-back from the front wall, a lower ridge and a clear gap to the boundary, and the drawings include a street elevation so the effect on the gap between houses can be seen rather than argued about.
On the Foley Road roads, very large detached houses sit on wide, deep plots laid out in an informal grid, and the assessment expects development there to include extensions to existing properties. Across Hare Lane, Oaken Lane and Telegraph Lane, houses set back behind front boundaries generally share a building line within each road, which a front or side addition should respect.
Sources: Elmbridge Borough Council: Companion guide - Claygate (Design and Character SPD, April 2012); Elmbridge Borough Council: Design Code SPD page
Permitted development, conservation areas and the Green Belt
Inside a conservation area or outside one, a single-storey rear extension can be permitted development if its depth past the original rear wall is 4 metres or less for a detached house, or 3 metres or less for any other house, and it meets the other limits, one of which is that buildings other than the original house may not cover more than half of the curtilage, leaving out the ground the original house stands on.
Inside Claygate Village or the Claygate Foley Estate those rights narrow, because the law classes conservation areas as article 2(3) land. A side extension, or a rear extension of more than one storey, is not permitted development there and needs a householder application.
Where permitted development does apply, the materials used outside must look similar to those of the existing house, conservatories aside.
The flood assessment measures 60% of Claygate's settlement area as Green Belt, and Core Strategy policy CS11 says the surrounding Green Belt will continue to be protected. If a plot falls inside it, an extension is judged against the Green Belt test described on our Elmbridge page, so we check the boundary for the address before sketching anything.
A householder application also needs the council's Design Code Checklist, and in a conservation area most applications need a Heritage Statement. Core Strategy policy CS11 asks new development in either Claygate conservation area to enhance its heritage value, so the statement explains how the extension does that.
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: Level 1 Strategic Flood Risk Assessment, April 2024 (AECOM); Elmbridge Borough Council: Elmbridge Core Strategy; Elmbridge Borough Council: Design Code SPD page; Elmbridge Borough Council: About conservation areas
Clay, slopes and drainage under a Claygate extension
The council's flood assessment describes the settlement area as underlain by the Claygate Member, the upper part of the London Clay Formation, and by the London Clay Formation itself, and as mainly free of superficial deposits. We have the structural engineer design the foundations from trial holes and the position of nearby trees, not from a standard detail.
For rainwater, the same assessment finds opportunities for bespoke infiltration drainage across most of the settlement area, so a soakaway is tested on site before it appears on a drawing.
Approximately 96% of Claygate is in Flood Zone 1. On the low western side, near the River Rythe, the assessment places Flood Zones 2 and 3 along the edge of the settlement and notes small areas with potential for groundwater flooding, so for plots on that side we check the flood maps before the new floor level is set.
Around Ruxley the varied topography often leaves houses split level within their plots. An extension there may need its own retaining walls and steps, which we draw from a levels survey.
Sources: Elmbridge Borough Council: Level 1 Strategic Flood Risk Assessment, April 2024 (AECOM); Elmbridge Borough Council: Companion guide - Claygate (Design and Character SPD, April 2012)
Party walls, trees and building control
Building on or at the boundary, or digging below and near the foundations of a neighbour's house, means telling the neighbours under the party wall rules. They cannot stop lawful work, but they can affect how and when it is carried out, so notices go out well before the start.
The 2012 assessment recorded concern over the potential loss of trees in gardens and streets. In a conservation area, a tree without a Tree Preservation Order is still protected under section 211 of the Town and Country Planning Act 1990, and the council may treat a planning application that includes specified tree work as the section 211 notice if the application clearly says it should.
Extending a home is work that may need building control approval, and that approval is separate from planning permission. In Claygate it 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 private registered building control approver.
During the build we protect the house, the garden and the trees we are keeping, run materials along one agreed route, and book the engineer's and building control's inspections at foundation, drainage and structural stages. At handover you receive the completion certificate and drawings of what was actually built.
Outside Claygate, 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: GOV.UK: Party walls and building work - work you must tell your neighbour about; GOV.UK: Party walls and building work - overview; Elmbridge Borough Council: Companion guide - Claygate (Design and Character SPD, April 2012); GOV.UK: Tree Preservation Orders and trees in conservation areas (planning guidance); Elmbridge Borough Council: Building control; GOV.UK: Building regulations approval - when you need approval; legislation.gov.uk (The National Archives): The Surrey (Structural Changes) Order 2026 (S.I. 2026/264); Hampstead Renovations: Holland Avenue, Wimbledon SW20 case study
House Extensions in Claygate: Questions
Is my Claygate house in the Green Belt, and how big can the extension be?
It depends on the plot. The council's flood assessment measures Claygate's settlement area as 60% Green Belt and the Core Strategy describes the village as almost totally encircled by it, so we check the boundary for the address first. Inside the Green Belt, size is judged by the council's Green Belt test, which we explain on our Elmbridge page rather than turn into a figure here. Outside it, the permitted development limits or the council's design policies set the size.
Can I build a rear extension in Claygate under permitted development?
In or outside the conservation areas a single-storey rear extension can be, if it projects 4 metres or less from the original rear wall of a detached house, or 3 metres or less for other houses, uses similar-looking materials and meets the other limits. Inside Claygate Village or the Foley Estate, a rear extension of more than one storey is not permitted development. We establish how the house was first built, and what has been added since, before relying on the rules.
Does an extension in the Claygate Village conservation area need planning permission?
A side extension does, and so does a rear extension of more than one storey, because a conservation area is article 2(3) land, where both fall outside permitted development. A single-storey rear extension within the limits may not. Most applications in a conservation area need a Heritage Statement, and Core Strategy policy CS11 asks for new development there to enhance the area's heritage value.
How does the flood zone affect an extension in Claygate?
The council's flood assessment defines approximately 96% of Claygate as Flood Zone 1. The Zone 2 and 3 land is Green Belt on the western edge near Milbourne Lodge Senior School, and the area at risk in a 1 in 30 year flood from the River Rythe includes the developed area of Station Road. Surface water is mapped in low points too, so we check the address and set floor levels and drainage to suit; the borough's flood rules are on our Elmbridge page.
Who inspects an extension in Claygate for the building regulations?
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, unless you choose a private registered building control approver. Building regulations approval is different from planning permission and you might need both. We book the inspections at the stages the building control body asks to see.
What happens at a feasibility visit for an extension in Claygate?
We walk the house and the whole plot with you, measure the rear and side elevations, note the boundaries, the neighbours' windows, the trees and the drains, and look at how the roof could meet a new one. Afterwards we confirm the planning route for the address, whether party wall notices and an engineer's ground investigation are needed, and what the measured survey must cover.
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