Two-storey extensions for semi-detached houses in Garforth
Our two-storey extensions for semi-detached houses service in Garforth covers everything: measured survey, design, planning or permitted development checks, structural design, building control and the build itself.
Garforth: the key facts for this kind of project.
- Postcode districts
- LS15 and LS25
- County / area
- West Yorkshire, England
- Price region
- Yorkshire and the Humber
- Guide price
- £51,500–£69,500 (£1,840–£2,480 per m²)
- Approval route
- Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension needs planning permission.
- Nearest towns
- Kippax (1.8 miles), Castleford (4.6 miles), Lofthouse (6.4 miles)
- Distance to Leeds
- about 6.8 miles
- First visit
- Free, no obligation
About a two-storey extension for a semi-detached house
A two-storey extension for a semi-detached house is a two-floor addition to the rear, the open side, or both, designed around the attached neighbour on one side. The rear is often the simplest option and can sometimes be permitted development, while a side extension uses the gap on the detached side. Both need care with the shared party wall and the neighbour's light.
Around Garforth we also work in Kippax, Castleford and Lofthouse, and across the rest of West Yorkshire. Postcode districts in and near Garforth: LS15 and LS25.
What it costs in Garforth
Most of the cost of a two-storey extension for a semi-detached house is set by its size and specification. For Garforth and the rest of Yorkshire and the Humber, our guide is £1,840–£2,480 per m² including VAT, so about £51,500–£69,500 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). Keep a contingency of around 10% for things nobody can see until the ground is opened up.
| Spec | Per m² | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £1,690–£2,290 per m² | £47,500–£64,000 |
| Standard | £1,840–£2,480 per m² | £51,500–£69,500 |
| Premium | £2,210–£2,980 per m² | £62,000–£83,500 |
Planning and building regulations in Garforth
In England, a two-storey rear extension on a semi can be permitted development if it goes no more than 3 m beyond the original rear wall and stays 7 m from the rear boundary, with matching materials and roof pitch. A two-storey side or wraparound extension always needs planning permission, costing £548 (or £575 for applications made from 8 December 2026). Protected areas such as conservation areas exclude two-storey rear permitted development.
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 Garforth homes
Rear, side or both
On a semi, a rear extension sits against the attached neighbour, while a side extension faces the detached neighbour and the street. We compare the space, cost and approval route for each, and for a wraparound, before you commit to one design.
The attached neighbour's light
A two-storey rear extension next to the party wall can take light from the neighbour's rear windows. Councils often use a 45-degree test, so the first floor may need to be shorter than the ground floor or set in from the shared boundary.
How we'd run your project
Free site visit
We visit your home in Garforth, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
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 hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.
Questions about two-storey extensions for semi-detached houses in Garforth
Who handles building regulations for a project in Garforth?
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.
How much does a two-storey extension for a semi-detached house cost in Garforth?
Our guide for Yorkshire and the Humber, which covers Garforth, is £1,840–£2,480 per m² including VAT. A typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £51,500–£69,500. 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 extension for a semi-detached house in Garforth?
Garforth is in England, so England planning rules apply. Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension needs planning permission. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
What if my neighbour has already extended?
That often helps. An existing extension next door can reduce the effect of yours on their light, and may show what the council accepts on your street. It can also mean building alongside their wall, so we check its position, foundations and any windows facing your plot at the survey.
Will a side extension make my semi look like a terrace?
It can if it fills the whole gap to the boundary at first floor and the neighbour does the same. Many councils ask for a first-floor gap to the side boundary or a set-back for this reason. We design the extension to keep the semi reading as one of a pair.
Nearby
Other towns near Garforth:
Other extensions in Garforth
- Rear
- Side
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Garforth · Two-storey extensions for semi-detached houses across West Yorkshire
Tell us about your house in Garforth and we'll call you back to arrange a free, no-obligation visit.