Conservatory replacement extensions in Swanley: design, approvals and build
If you live in Swanley and want more space without moving, a conservatory replacement is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in SwanleyFrom £22,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–14 weeks on site
- Postcode districtsBR8
Planning rules that apply in Swanley
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
Local to Swanley
Across BR8, we can visit, measure and advise. We also work in nearby Dartford (4 miles), Sevenoaks (9 miles), Gravesend (9 miles), Strood (13 miles).
For homes towards Greater London, Bexley is around 3 miles away. In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
What should I budget for a conservatory replacement in Swanley?
For Swanley we adjust our national guide rates by ×1.12, the factor we use for South East England. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Swanley: £2,070 to £3,920 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 3.3 m 10 m² | £22,000 – £27,000 | £24,000 – £31,000 | £30,500 – £39,500 |
| 3.5 m × 4 m 14 m² | £29,000 – £34,500 | £33,500 – £43,500 | £43,000 – £55,000 |
| 4 m × 5 m 20 m² | £41,000 – £49,500 | £48,000 – £62,000 | £61,500 – £78,500 |
Includes removal of the old conservatory. Reusing existing foundations is only possible after investigation.
For a figure based on your own dimensions, use our guide-price tool.
Is a conservatory replacement right for your house?
- Homes where the conservatory sits unused
- Older uPVC conservatories near the end of their life
- Conservatories that are too hot or too cold
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Swanley
Do you cover all of Swanley?
Yes. We cover Swanley and the surrounding parts of Kent. Site visits are free and there is no obligation.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Swanley, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Will my neighbours in Swanley be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Can I keep the existing base?
Sometimes, but conservatory bases are often too shallow for solid walls. Trial holes tell us before we confirm the price.
Is it worth replacing a conservatory with an extension?
If the conservatory is unusable for much of the year, usually yes. A solid extension gives a heated room that counts as proper living space. Our guide range is about £2,070 to £3,920 per m² including VAT, including removal.
Book a free site visit in Swanley
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.