Greenwich side extensions, designed and built
A side extension in Greenwich starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in GreenwichFrom £28,500 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsSE3, SE4, SE8, SE10, SE13
Do I need planning permission in Greenwich?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
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 regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
How much does a side extension cost in Greenwich?
Labour and material costs vary across the UK, so for Greenwich we use our London factor (×1.3). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Greenwich: £2,280 to £4,420 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £28,500 – £34,500 | £31,500 – £41,500 | £40,500 – £53,500 |
| 3 m × 6 m 18 m² | £40,500 – £49,500 | £47,500 – £62,500 | £60,500 – £80,000 |
| 3 m × 8 m 24 m² | £54,500 – £66,000 | £63,500 – £83,000 | £81,000 – £106,500 |
For a figure based on your own dimensions, use our guide-price tool.
Local to Greenwich
Postcode districts we cover around Greenwich include SE3, SE4, SE8, SE10, SE13, SE14. We also work in nearby New Cross (1 mile), Blackheath (1 mile), Brockley (1 mile), Catford (2 miles).
In London, space is at a premium and gardens are often short, so side returns, wraparounds and carefully planned rear extensions tend to make the most of every metre.
Included in a typical project
- Planning route checked or application made
- Structure, roof tied into the house
- New openings through the side wall
- Windows, doors and finishes to match
- Survey, design and street-view drawings
- Foundations near boundaries and any drains
Councils often prefer side extensions to sit slightly back from the front of the house with a lower roof, so the original building still reads clearly. We design to those principles from the start to avoid redesigns.
How the project works
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Common questions in Greenwich
Will my neighbours in Greenwich 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 see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Greenwich, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Greenwich?
Yes. We cover Greenwich and the surrounding parts of Greater London. Site visits are free and there is no obligation.
How close to the boundary can I build?
It depends on height. In England, within 2 m of a boundary the eaves must not exceed 3 m under permitted development. Building on the boundary is possible but brings party wall and maintenance access issues we plan for.
How much does a side extension cost?
Our guide range is about £2,280 to £4,420 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £47,500 to £62,500 in Greenwich.
Book a free site visit in Greenwich
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.