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 Kempston Hardwick?
In Kempston Hardwick, a double-storey extension typically costs £1,750–£2,650 per m² of floor area (both floors), including VAT at 20% (standard rate). For a typical 36 m² project that is roughly £63,000–£95,500. That range is adjusted for the East of England, where domestic building work typically costs around 6% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (25 m²) | £44,000–£66,000 |
| Typical project (36 m²) | £63,000–£95,500 |
| Larger project (50 m²) | £87,500–£132,500 |
| Rate per m² | £1,750–£2,650 |
What moves the price most:
- Brick matching and external finishes
- Steel beams where walls are opened up
- Scaffolding and access to the rear
- Bathrooms or en-suites on the first floor
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a double-storey extension in Kempston Hardwick?
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.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
From survey to sign-off, the job normally involves:
- Foundations, drainage and scaffolding
- Building control sign-off
- Windows, doors and staircase alterations
- Electrics, heating, plumbing and plastering
- Brick or block walls, floors and a roof tied into the house
- Design drawings and planning application
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 Kempston Hardwick
Across the East of England, 1930s and post-war semis, newer estates and rural cottages all feature, each with different extension and loft options.
From MK45 outwards, we take on projects throughout Kempston Hardwick and the surrounding parts of Bedfordshire.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about double-storey extensions in Kempston Hardwick
How much does a double-storey extension cost in Kempston Hardwick?
In Kempston Hardwick, a double-storey extension typically costs £1,750–£2,650 per m² of floor area (both floors), including VAT at 20% (standard rate). A typical 36 m² project comes to roughly £63,000–£95,500. 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.
Who approves a double-storey extension in Kempston Hardwick?
Planning matters in Kempston Hardwick go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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.
Is a double-storey extension cheaper per square metre?
Usually yes. You pay for one set of foundations and one roof but get two floors of space, so the cost per square metre is often lower than a single-storey extension.