New Cross annexe extensions, designed and built
If you live in New Cross and want more space without moving, an annexe extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in New CrossFrom £71,500 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsSE4, SE8, SE10, SE14, SE15
Will the council need to approve it?
In England an annexe that stays part of the household and connects to the house is assessed as an extension, but its size usually takes it beyond permitted development, so a householder application describing the ancillary use is the normal route.
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.
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).
Included in a typical project
- Planning application describing ancillary use
- Separate or shared heating and hot water
- Design for accessibility: level thresholds, wider doors, walk-in shower
- Fire separation and alarms to building regulations
Annexe extension prices in New Cross
For New Cross we adjust our national guide rates by ×1.3, the factor we use for London. Figures include VAT; your written quote after the survey replaces them.
Typical rates in New Cross: £2,600 to £4,940 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Studio annexe 25 m² | £71,500 – £89,500 | £78,000 – £97,500 | £97,500 – £123,500 |
| One-bedroom annexe 35 m² | £91,000 – £114,000 | £109,000 – £136,500 | £136,500 – £173,000 |
| Larger annexe 45 m² | £117,000 – £146,500 | £140,000 – £175,500 | £175,500 – £222,500 |
Try the guide-price tool to see a range for your own size and finish.
Extensions in and around New Cross
Postcode districts we cover around New Cross include SE4, SE8, SE10, SE14, SE15, SE16. We also work in nearby Brockley (1 mile), Greenwich (1 mile), Peckham (1 mile), Blackheath (2 miles).
Just over the Kent border, Swanley is about 11 miles away. London's housing is dominated by Victorian and Edwardian terraces, many with a rear outrigger and a side return, and 1930s semis in the outer boroughs. Conservation areas are common, so the planning check comes first.
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
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
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 New Cross
How long does an annexe extension take to build in New Cross?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 10–16 weeks design and approvals.
Will my neighbours in New Cross 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.
Who do I contract with for an annexe extension in New Cross?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Will an annexe affect council tax?
It can. Some annexes are assessed separately for council tax, with discounts or exemptions in some cases when occupied by a relative. Check with the Valuation Office Agency (England and Wales), your local assessor (Scotland) or Land & Property Services (Northern Ireland).
Does an annexe extension need planning permission?
Usually yes, because of its size and the way it will be used. Councils check that it stays ancillary to the main house, so the application must describe the use clearly.
Book a free site visit in New Cross
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.