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 Nelson?
In Nelson, a double-storey extension typically costs £1,550–£2,350 per m² of floor area (both floors), including VAT at 20% (standard rate). For a typical 36 m² project that is roughly £56,000–£84,500. Prices across the North West are typically 6% below the UK average for this kind of work, which is reflected in the range for Nelson. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (25 m²) | £39,000–£59,000 |
| Typical project (36 m²) | £56,000–£84,500 |
| Larger project (50 m²) | £77,500–£117,500 |
| Rate per m² | £1,550–£2,350 |
What moves the price most:
- Steel beams where walls are opened up
- Total floor area across both floors
- Bathrooms or en-suites on the first floor
- Scaffolding and access to the rear
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 Nelson?
Approvals for a double-storey extension in Nelson 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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
What we take care of:
- Building control sign-off
- Structural engineer’s calculations
- Opening up at both levels with steel beams
- Electrics, heating, plumbing and plastering
- Windows, doors and staircase alterations
- Foundations, drainage and scaffolding
How long does it take?
Allow 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 Nelson
Terraced streets across the North West often suit rear dormers and single-storey kitchen extensions.
Projects in Nelson (BB9) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 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 Nelson
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.
Does a double-storey extension need planning permission?
Usually. In England a two-storey rear extension can only be permitted development if it is no more than 3 metres deep and at least 7 metres from the rear boundary, and side extensions over one storey always need permission. In practice most are approved through a planning application.
Do you build double-storey extensions in Nelson?
Yes. We build double-storey extensions across Nelson, including postcodes BB9. Every project starts with a free home visit.
How much does a double-storey extension cost in Nelson?
In Nelson, a double-storey extension typically costs £1,550–£2,350 per m² of floor area (both floors), including VAT at 20% (standard rate). A typical 36 m² project comes to roughly £56,000–£84,500. 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.