What is a double-storey extension?

A double-storey extension (also called a two-storey extension) adds rooms on both the ground and first floor in one build. It typically gives a larger kitchen or living space downstairs and an extra bedroom or bathroom above.
How much does a double-storey extension cost in Bradford?
In Bradford, a double-storey extension typically costs £1,550–£2,300 per m² of floor area (both floors), including VAT at 20% (standard rate). For a typical 36 m² project that is roughly £56,000–£83,000. Building costs in Yorkshire and the Humber run about 7% below the UK average, and the figures for Bradford are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (25 m²) | £39,000–£57,500 |
| Typical project (36 m²) | £56,000–£83,000 |
| Larger project (50 m²) | £77,500–£115,000 |
| Rate per m² | £1,550–£2,300 |
The main things that change the cost:
- Bathrooms or en-suites on the first floor
- Total floor area across both floors
- Brick matching and external finishes
- Steel beams where walls are opened up
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a double-storey extension in Bradford?
Here is how the rules work for a double-storey extension in England. In England an extension of more than one storey can only be permitted development at the rear, no more than 3 metres deep and at least 7 metres from the rear boundary, with matching materials and any upper side windows obscure-glazed. Most double-storey extensions therefore go through a householder planning application.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
We check this for your address before design work starts, so there are no surprises later.
What we handle
What we take care of:
- Foundations, drainage and scaffolding
- Building control sign-off
- Design drawings and planning application
- Structural engineer’s calculations
- Electrics, heating, plumbing and plastering
- Brick or block walls, floors and a roof tied into the house
How long does it take?
The build itself usually takes 14 to 20 weeks on site, after planning and building control approval. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Bradford
Yorkshire and the Humber has stone and brick terraces as well as inter-war and newer estates, so materials matching is an early design question.
We work across Bradford and neighbouring areas such as Shipley, Pudsey and Cleckheaton. Postcodes we cover in Bradford include BD1, BD2, BD3 and BD5.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about double-storey extensions in Bradford
How long does a double-storey extension take in Bradford?
Typically 14 to 20 weeks on site, after planning and building control approval. Design and approvals beforehand usually take 3 to 4 months.
How much does a double-storey extension cost in Bradford?
In Bradford, a double-storey extension typically costs £1,550–£2,300 per m² of floor area (both floors), including VAT at 20% (standard rate). A typical 36 m² project comes to roughly £56,000–£83,000. Your fixed price depends on the survey and drawings.
Can I live at home during the work?
Most families stay put. The shell is built first and the house is opened up late in the job, so disruption inside is limited to a few weeks.
Will the first floor need a new staircase?
Not normally. The new rooms are reached from the existing landing, though a doorway or short corridor may need to be formed.
What drawings do I need?
Planning drawings for the application, then more detailed building regulations drawings and structural calculations for building control. We prepare both.
