Area guide · KT13
House Extensions in St George's Hill (KT13)
Extending a house on St George's Hill? Then you already know the estate does nothing by halves. This is a gated private estate of wooded plots running to an acre and more, where substantial modern classical mansions stand among pines and silver birch, where the tennis and golf clubs keep life inside the gates, and where total privacy is the currency. Many houses have been replaced wholesale over the decades, so the stock is newer than it looks and the briefs sit at the very top of our range: whole-house programmes, basement leisure floors and double-storey reworks at the scale the estate expects. Every project answers to two authorities at once, Elmbridge Borough Council for planning and the residents' association under the estate covenants for external works, and the two consents have to be read together from the first sketch. That double gate is exactly the kind of work we exist for.
Live planning data
Two approvals, one design
Nothing gets built on St George's Hill on a planning permission alone. The estate covenants give the residents' association a say over external works, and that consent sits alongside whatever Elmbridge decides, so a scheme that pleases the council but jars with the estate goes nowhere. We treat the covenant review as a design brief in its own right: composition, materials and massing worked out with both readers in mind, then both submissions prepared and progressed in parallel.
Approached that way, the estate is generous territory. Plots of an acre carry serious additions without crowding anything, mature pines screen most work from every neighbour, and the modern classical language of the houses gives a clear grammar to extend within. This is the method our whole luxury extensions service is built on, and the Hill is where it earns its keep.
Local knowledge
The stock behind the gates
The modern classical mansions. The estate's signature houses are broad, symmetrical and built to a specification most of the country never sees. Extending one is a matter of continuing its logic: a new wing that picks up the existing rhythm, a rear elevation reworked in matching stone and render, interiors reorganised around how the family actually lives.
The replacement generation. A large share of St George's Hill houses were rebuilt wholesale in recent decades. Where the volume already exists, the natural brief is usually reconfiguration plus extension: opening cellular ground floors, adding a glazed garden room, and lifting finishes to the estate's current standard.
The tennis club side. Around the estate's tennis club, houses trade on their position inside the Hill's private sporting life. Owners here tend to commission leisure wings: pools, gyms and entertaining spaces that carry the club lifestyle into the home.
The wooded acre plots. Among the pines and silver birch, the constraint is rarely space and almost always trees. We survey root zones before designing anything, then site the addition where the canopy allows, which also happens to be what the council and the estate both want to see.
Every street is different. That's the point.
We design to St George's Hill's stock and to what the council demonstrably approves — not to a template. A free site visit tells you what your house can take.
Get my free estimateHonest numbers
What an extension costs in St George's Hill in 2026
Prices on the Hill reflect the specification the estate expects. The ranges below cover the build itself and leave out VAT, professional fees and kitchen fit-out:
| Extension type | Typical St George's Hill cost | On-site time | Usual planning route |
|---|---|---|---|
| Single-storey rear | £70,000 to £140,000 | 3 to 4 months | Planning or PD, estate consent in every case |
| Kitchen extension (incl. mid-range kitchen) | £85,000 to £165,000 | 3 to 4 months | Planning or PD, estate consent in every case |
| Wrap-around extension | £110,000 to £205,000 | 4 to 6 months | Full application plus estate consent |
| Double-storey rework | £120,000 to £260,000 | 5 to 7 months | Full application plus estate consent |
| Basement leisure floor | Priced on design | 6 to 12 months | Full application plus estate consent |
| Whole-house programme | Priced on design | Phased programme | Design-led application plus estate consent |
Budget to £3,800 to £6,000 per square metre at this end of the market. How the larger programmes band out is set out in our luxury extension cost guide; your own figure arrives as a fixed, itemised quote after a free design visit, and it does not move afterwards.
Permissions, handled
Planning on the Hill, demystified
Covenants come first. Estate consent applies to external works whatever the planning position, so even a project with permitted development rights goes past the residents' association. We prepare that submission with the same care as the council's.
PD exists but rarely decides anything. Where rights remain, we document any qualifying element with a Lawful Development Certificate, though on the Hill the covenant layer means PD is a supporting act rather than the route.
Trees shape the siting. Mature pines and birch are the estate's character and the officers' concern in equal measure. Early arboricultural input keeps both consents on side.
Timescales and party walls. Elmbridge determines householder applications in roughly eight weeks, and we run the process from first drawing to decision notice. Where the Party Wall Act is engaged, most often on basements, budget £1,000 to £2,500 for each neighbour whose surveyor is appointed, though acre plots keep many projects clear of it entirely.
How it works
How it works
- Free design visit. We walk the plot, read the covenant position for your house, and give you a straight view on scope and budget.
- Design and drawings. One scheme written in the estate's architectural language and composed to clear both consents.
- Approvals, run in parallel. Elmbridge application and residents' association submission managed together to decision.
- Fixed-price build. An itemised contract figure, a team accustomed to working behind gates, and a clean, documented handover.
Questions, answered
St George's Hill extension FAQs
Do I need estate consent as well as planning permission?
Yes. The covenants give the residents' association a role in approving external works, in addition to Elmbridge's planning decision. We prepare both submissions and run them concurrently so neither holds up the other.
What does an extension cost on St George's Hill?
Work to £3,800 to £6,000 per square metre in 2026. Single-storey rears typically run £70,000 to £140,000 and double-storey reworks £120,000 to £260,000, while basements and whole-house programmes are priced on design. Every figure we quote is fixed and itemised.
Is a basement the right move here?
Often. On seven-figure to eight-figure houses a leisure floor below ground adds a swimming pool, gym or cinema without touching the estate's treasured outward calm, and the plot sizes make the engineering manageable.
Can permitted development be used on the estate?
Sometimes in planning terms, but the covenants apply regardless, so estate consent is still needed. Where PD genuinely helps, we secure a Lawful Development Certificate to put the position beyond doubt.
How long from first visit to finished project?
Design typically takes several weeks, the council decision around eight, with estate consent progressed alongside. Site time runs from three months for a single-storey scheme to a phased year or more for a whole-house programme.
Will the work compromise our privacy?
Protecting it is part of the design. Screening trees stay, siting keeps work invisible from the road, and our site teams understand the discretion the estate expects.
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What clients say
Rated 5.0 on Google
“Used The Extension Company for a loft conversion on our semi detached in Barnet and couldn't be happier. They explained what was possible at the first visit, sorted the planning side, and gave a fixed price with no surprises at the end.…” read the full review
“Really impressed with the entire project. The side extension and conservatory have been finished to a very high standard and the team made the process straight forward and stress-free. It’s transformed the space and added so much value, would definitely recommend.”
“Brilliant experience with the extension company, transparent from the word go. Completed a double story extension for me and I couldn’t be more pleased. Thank you”
“I got the extension company to do a bathroom refurb for us a January they done a great job they managed to fit in a large shower as well as a bath”
Reviews shown word for word from our Google profile. Read all 8 reviews on Google
Free site visit
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Free site visit anywhere in St George's Hill, honest feasibility advice and a fixed, itemised price — design, planning and build handled end to end by the Pine Grove team.
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