Two-storey side extensions in Knowle
Homes in Knowle with a bit of space to the side or rear can often take a two-storey side extension. We'll tell you honestly whether yours can, and what approvals it needs.
What we'd confirm first for a project in Knowle.
- Postcode districts
- B93
- County / area
- West Midlands, England
- Price region
- West Midlands
- Guide price
- £86,000–£115,500 (£2,050–£2,750 per m²)
- Approval route
- Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
- Nearest towns
- Solihull (2.9 miles), Shirley (West Midlands) (4.1 miles), Acocks Green (5.8 miles)
- Distance to Birmingham
- about 9.8 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 district B93 in and around Knowle, along with neighbouring Solihull, Shirley (West Midlands) and Acocks Green.
What it costs in Knowle
Guide prices for two-storey side extensions in the West Midlands are around £2,050–£2,750 per m² of new floor space, including VAT. For a typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space), that's roughly £86,000–£115,500. 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 | £1,890–£2,530 per m² | £79,000–£106,500 |
| Standard | £2,050–£2,750 per m² | £86,000–£115,500 |
| Premium | £2,460–£3,300 per m² | £103,500–£138,500 |
Planning and building regulations in Knowle
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 Knowle homes
Side windows, boundaries and gutters
Upstairs windows in the side wall face the neighbour, so they are usually obscure-glazed and fixed, or left out. Building close to the boundary also raises questions about foundations, overhanging gutters and access for maintenance, so we design the eaves and gutter to stay within your land.
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
Look at the house
We start in Knowle with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.
Questions about two-storey side extensions in Knowle
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 Knowle?
We cover Knowle (B93) and nearby places including Solihull, Shirley (West Midlands) and Acocks Green, plus the rest of the West Midlands. The first site visit is free.
How much does a two-storey side extension cost in Knowle?
Our guide for the West Midlands, which covers Knowle, is £2,050–£2,750 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 £86,000–£115,500. 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 Knowle?
Knowle 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.
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
We also cover places near Knowle, including:
Other extensions in Knowle
- 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 Knowle · Two-storey side extensions across the West Midlands
Want a figure first? Try our guide price tool, then book a free visit to firm it up.