Two-storey side extensions in Edgware
We cover Edgware and the rest of Greater London for two-storey side extensions. Start with a free site visit and a plain-English view of what your house and plot can take.
Edgware: the key facts for this kind of project.
- Postcode districts
- HA8, NW7 and NW9
- 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
- Harrow Weald (2.7 miles), Wealdstone (2.8 miles), Borehamwood (2.9 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 postcode districts HA8, NW7 and NW9 in and around Edgware, along with neighbouring Harrow Weald, Wealdstone and Borehamwood.
What it costs in Edgware
Most of the cost of a two-storey side extension is set by its size and specification. For Edgware and the rest of London, our guide is £2,460–£3,300 per m² including VAT, so about £103,500–£138,500 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.
| 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 Edgware
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 Edgware homes
Set-down and set-back
Councils usually want a two-storey side extension to look subordinate to the house. Setting the front wall back from the main front and dropping the ridge slightly below the main roof helps it read as an addition, and is often expected in local design guidance.
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
Start at your house
We come to your home in Edgware, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Design and approvals
We draw the extension and check it against the rules for England, then apply for planning permission or a certificate of lawfulness, whichever fits.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.
Questions about two-storey side extensions in Edgware
How long does a two-storey side extension take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Which postcodes do you cover around Edgware?
We cover Edgware (HA8, NW7 and NW9) and nearby places including Harrow Weald, Wealdstone and Borehamwood, plus the rest of Greater London. The first site visit is free.
Do I need planning permission for a two-storey side extension in Edgware?
Edgware 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 Edgware?
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 Edgware:
Other extensions in Edgware
- 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 Edgware · Two-storey side extensions across Greater London
Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Edgware.