Two-storey side extensions in Hadley Wood
For a two-storey side extension in Hadley Wood, the first questions are always the same: how big, which approvals, and what it will cost. This page answers all three for Greater London.
The basics for Hadley Wood at a glance.
- Postcode districts
- EN4
- County / area
- Greater London, England
- Price region
- London
- Guide price
- £103,500–£138,500 (£2,460–£3,300 per m²)
- Approval route
- Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
- Nearest towns
- New Barnet (1.2 miles), East Barnet (1.4 miles), Cockfosters (1.5 miles)
- First visit
- Free, no obligation
About a two-storey side extension
A two-storey side extension is a new two-floor addition built into the space beside your house, often over a driveway or side passage. It typically adds one or two bedrooms upstairs and a utility, study or larger kitchen below, without giving up rear garden.
We cover Hadley Wood (EN4) and the places around it, including New Barnet (1.2 miles), East Barnet (1.4 miles) and Cockfosters.
What it costs in Hadley Wood
A guide price for Hadley Wood: around £103,500–£138,500 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). That works out at £2,460–£3,300 per m² of new floor space, including VAT at 20%. Professional fees for drawings and the structural engineer are listed separately on our prices page.
| Spec | Per m² | A 3 m × 7 m footprint on two floors (42 m² of new floor space) |
|---|---|---|
| Essential | £2,260–£3,040 per m² | £95,000–£127,500 |
| Standard | £2,460–£3,300 per m² | £103,500–£138,500 |
| Premium | £2,950–£3,960 per m² | £124,000–£166,500 |
Planning and building regulations in Hadley Wood
In England, a two-storey side extension always needs householder planning permission, because permitted development only allows single-storey extensions beyond a side wall. The fee is £548 (or £575 for applications made from 8 December 2026), and councils should decide within 8 weeks of validation. Expect them to look at set-back, roof height, gaps to the boundary and the effect on neighbours.
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
Design points for Hadley Wood homes
Access and services
Side extensions often cover the only route to the back garden, a gas meter, soil pipes or a drain run. We plan bin and bike access, move meters and pipes where needed and check drains early, because these items affect both cost and layout.
Avoiding a terracing effect
Where semi-detached houses sit close together, side extensions on neighbouring houses can join up and turn a row of pairs into a terrace. Many councils ask for a gap to the boundary at first floor to stop this, so we check local guidance before fixing the width.
How we'd run your project
Visit and first ideas
One of our team visits your house in Hadley Wood, checks the walls, roof and drains, and sketches out options with you.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Build and sign-off
Vetted teams working under S&K build the extension, and we arrange the building control completion certificate at the end.
Questions about two-storey side extensions in Hadley Wood
Which postcodes do you cover around Hadley Wood?
We cover Hadley Wood (EN4) and nearby places including New Barnet, East Barnet and Cockfosters, plus the rest of Greater London. The first site visit is free.
How much does a two-storey side extension cost in Hadley Wood?
Our guide for London, which covers Hadley Wood, is £2,460–£3,300 per m² including VAT. A typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space) comes to about £103,500–£138,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
Do I need planning permission for a two-storey side extension in Hadley Wood?
Hadley Wood is in England, so England planning rules apply. Planning permission is needed: in England, permitted development only allows single-storey extensions to the side. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
Who handles building regulations for a project in Hadley Wood?
We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
Can I build a two-storey side extension over my driveway?
Yes, if the drive is wide enough for a useful room and the council accepts the design. You may lose off-road parking, which some councils weigh up, and the foundations need to suit the ground below. We check parking, drains and meter positions at the free site visit before any drawings are prepared.
Nearby
Other towns near Hadley Wood:
Other extensions in Hadley Wood
- Rear
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Hadley Wood · Two-storey side extensions across Greater London
Tell us about your house in Hadley Wood and we'll call you back to arrange a free, no-obligation visit.