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 Rawmarsh?
In Rawmarsh, 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 Rawmarsh 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 biggest cost drivers are:
- Bathrooms or en-suites on the first floor
- Steel beams where walls are opened up
- Roof design and how it joins the existing roof
- Scaffolding and access to the rear
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 Rawmarsh?
Approvals for a double-storey extension in Rawmarsh follow the rules for 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:
- Electrics, heating, plumbing and plastering
- Building control sign-off
- Design drawings and planning application
- Windows, doors and staircase alterations
- Opening up at both levels with steel beams
- Structural engineer’s calculations
How long does it take?
Build time is typically 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 Rawmarsh
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 Rawmarsh and neighbouring areas such as Rotherham, Chapeltown and Sheffield. Postcodes we cover in Rawmarsh include S62.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 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 sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about double-storey extensions in Rawmarsh
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.
How much does a double-storey extension cost in Rawmarsh?
In Rawmarsh, 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.
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.
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 Rawmarsh?
Planning matters in Rawmarsh go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
