Sevenoaks · TN13–TN15
House Extensions in Sevenoaks
Serving Sevenoaks & surrounding areas
Sevenoaks extensions almost always have to hold their own next to a Georgian or Victorian facade that's worth real money on resale, so the brief is as much about protecting kerb appeal as adding square footage. We design extensions that a Kippington estate agent wouldn't think twice about.
"We had our loft insulated and boarded. From start to finish the process was smooth, professional and stress-free. Malcolm upgraded the insulation and …"
House Extensions for Sevenoaks homes
Why Sevenoaks house extensions briefs are different
Sevenoaks District Council's conservation areas around the High Street, Knole and Kippington mean rear extensions on the town's best roads face close scrutiny on eaves height, brick bond and window proportion. We build the planning case around matched materials and a genuinely subordinate massing, which is what gets these through committee rather than delegated refusal.
Sevenoaks mixes Georgian townhouses around the High Street and Knole Park, red-brick Victorian villas in Kippington and Bradbourne, Arts-and-Crafts houses towards the Weald, and interwar and 1960s detacheds spreading out to Riverhead, Otford and Dunton Green.
Local considerations
Sevenoaks District Council oversees a dense patchwork of conservation areas around the High Street, Knole and Kippington, with several Article 4 directions removing permitted development rights on the town's most sought-after residential roads.
The greensand ridge running through the town gives firm sandstone bearing on higher ground but shifts to heavier clay on the lower slopes towards Riverhead, and the steep gradients around Kippington regularly call for retaining structures and staged foundations.
Extensions are where ground conditions, sightlines and neighbouring rights-of-light decisions cost real money if missed early. We front-load all three before any drawings are firmed up.
What Sevenoaks clients ask for
Most clients want clarity on fixed cost, end-to-end timeline and how disruptive the kitchen-relocation period will be — we put those in writing on day one.
Recent local project
We recently completed a 32m² glazed rear extension to a Victorian villa on Oakhill Road, using a reclaimed London stock brick plinth and slim steel-framed doors to keep the garden elevation quietly contemporary against a heritage frontage.
House Extensions on the ground in Sevenoaks
Most of our Sevenoaks extension enquiries come from the roads fanning out from Knole Park — Kippington Road, Bradbourne Vale Road and Hollybush Lane — where large Victorian and Edwardian villas sit on generous but often steeply sloping plots. Further out towards Riverhead and Dunton Green the housing stock is 1930s and 1960s detached, with flatter gardens and considerably more scope for a straightforward single-storey wrap-around. Otford and Seal bring a third character entirely: village-edge cottages and farmhouses where any extension has to read as a subordinate addition to a much older core. Where a Kippington plot backs onto the greensand slope, we've had to design stepped foundations into the extension budget more often than we would in the flatter parts of the district.
Materials and spec we use for Sevenoaks house extensions
On Sevenoaks conservation-area extensions we typically match soft red multi-stock brick or reclaimed London stock, laid in Flemish bond where the original elevation demands it — Sevenoaks District Council heritage officers are particular about mortar colour and joint profile on Kippington and High Street-facing properties. Roofs are natural slate or handmade clay plain tile depending on the host building, with cast-iron-effect aluminium rainwater goods rather than uPVC. Glazing is usually slim steel-look aluminium in a heritage-approved anthracite or bronze, and where the extension faces open garden rather than the street we'll push for larger glazed spans than the conservation officer would ever allow to the front. Insulation specs are pitched to Passivhaus-adjacent U-values given how many Sevenoaks clients are retrofitting the rest of the house to match.
How a Sevenoaks house extensions build actually runs
Sevenoaks District Council planning determinations typically run the full eight-week statutory period on conservation-area applications, and we always build in a pre-application enquiry for anything on Kippington Road, the High Street or within sight of Knole — it's usually a two-to-three week wait but saves far longer if the first submission comes back with objections. Access on the narrower lanes around Bayham Road and Hollybush Lane needs careful skip and delivery scheduling, since on-street parking is tight and permits from the council take around ten working days. Where a garden falls away sharply, as on several Kippington plots, we sequence groundworks around a structural engineer's staged excavation plan rather than a single dig, which adds time but avoids slope-stability surprises mid-build.
Realistic cost and timeline for house extensions in Sevenoaks
A single-storey rear extension of 25–35m² in Sevenoaks typically runs £110,000–£165,000 plus VAT (2026 prices), reflecting the town's higher specification expectations, over 16–20 weeks on site. Two-storey rear or side-return extensions on the larger Kippington and Bradbourne villas run £190,000–£280,000 over 22–28 weeks. The costs that push a Sevenoaks job to the top of the band are matched slate or handmade tile roofing, bespoke steel-framed glazing, and retaining structures on sloping Kippington and Weald plots — the last of these alone can add £15,000–£25,000 depending on the drop.
Our process
How a house extensions project in Sevenoaks runs
- Step 1
Free site visit & feasibility
We walk the property, measure boundaries, check drainage runs and explain what permitted development will and won't cover.
- Step 2
Concept design
Hand-sketched layouts that test 2–3 different footprints before we commit to drawings.
- Step 3
Planning & building regs
We manage the application in-house, including neighbour consultation and the lawful development certificate where needed.
- Step 4
Structural & MEP coordination
Engineer calcs, party wall awards and an early conversation with your electrician and plumber before we break ground.
- Step 5
Build & handover
One site manager from groundworks to snagging, with a written 5-year workmanship guarantee on completion.
Local coverage
Nearby villages, districts and neighbourhoods we cover from Sevenoaks
We deliver house extensions projects across Sevenoaks and the surrounding parishes — typically reachable within 20 minutes of our crew vans.
- Riverhead
- Otford
- Seal
- Dunton Green
- Weald
- Sundridge
- Kemsing
Don't see your village listed? We almost certainly still cover it — get in touch.
FAQs
House Extensions in Sevenoaks — frequently asked
Will my Sevenoaks extension need planning permission?
Most rear extensions on conservation-area properties around Knole, the High Street and Kippington need full planning consent rather than relying on permitted development — we check your specific Article 4 status at the free site visit.
How long does Sevenoaks District Council take to decide?
Straightforward applications are usually determined within the eight-week statutory period; conservation-area and listed-building consents can run to ten or twelve weeks, which we factor into your written programme.
Will I need to move out during the extension build?
On most rear extensions you can stay in the house. Phasing the kitchen break-through is where it gets disruptive — we usually move that to week 8–10 once the new envelope is dry.
What's the largest extension you can build under permitted development?
Up to 4m deep for a detached house and 3m for a semi/terrace (8m and 6m under the larger neighbour-consultation route until 2025). We confirm yours at survey.
Do you take on whole-house refurbishments in Sevenoaks?
Yes. Full refurbishments of Edwardian villas are regular work — rewiring, replumbing, insulation upgrades, joinery and decoration under one written contract.
Are you fully insured for work in Sevenoaks?
Yes — £5m public liability and £10m employer's liability covering all sites in Sevenoaks and across Kent and East Sussex. Certificates available on request.
Popular project combinations
Often paired with house extensions in Sevenoaks
Clients who book house extensions in Sevenoaks often combine it with one of these services for a more complete transformation.
Loft Conversions
A natural pairing for house extensions — most Sevenoaks clients have us quote both at the same survey to save a second visit.
View serviceBespoke Kitchens
A natural pairing for house extensions — most Sevenoaks clients have us quote both at the same survey to save a second visit.
View serviceKitchen Refurbishments
A natural pairing for house extensions — most Sevenoaks clients have us quote both at the same survey to save a second visit.
View serviceAlso available nearby
House Extensions in nearby towns
In short
For house extensions in Sevenoaks (TN13–TN15), Tembok delivers a single accountable team, a fixed-price written quote and a 5-year workmanship guarantee. Book a free site visit anywhere from Riverhead to Otford and we'll tell you plainly what Sevenoaks District Council is likely to approve.
Ready to price your house extensions in Sevenoaks?
Free site visit, fixed-price written quote and a 5 year workmanship guarantee — backed by 40+ years on the tools and our workshop in Biddenden.
"We had our loft insulated and boarded. From start to finish the process was smooth, professional and stress-free. Malcolm upgraded the insulation and …"
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One team, one quote, one point of accountability — from design through to handover.