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 South Elmsall?
In South Elmsall, 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. Prices across Yorkshire and the Humber are typically 7% below the UK average for this kind of work, which is reflected in the range for South Elmsall. 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 |
What moves the price most:
- Roof design and how it joins the existing roof
- Scaffolding and access to the rear
- Bathrooms or en-suites on the first floor
- Steel beams where walls are opened up
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a double-storey extension in South Elmsall?
The approval route for South Elmsall is set by planning law 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
What we take care of:
- Structural engineer’s calculations
- Electrics, heating, plumbing and plastering
- Design drawings and planning application
- Foundations, drainage and scaffolding
- Opening up at both levels with steel beams
- Building control sign-off
How long does it take?
The build itself usually takes 14 to 20 weeks on site, after planning and building control approval. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in South Elmsall
In Yorkshire, through-terraces and back-to-backs have particular constraints, while semis and detached houses suit larger extensions.
Projects in South Elmsall (WF9) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about double-storey extensions in South Elmsall
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.
How close can it be to my neighbour?
Councils look at loss of light and outlook for neighbours. Many apply a 45-degree guideline from the nearest neighbouring window. We design to the council’s published guidance to give the application the best chance.
How much does a double-storey extension cost in South Elmsall?
In South Elmsall, 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.
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.
Who approves a double-storey extension in South Elmsall?
Planning matters in South Elmsall go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
