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 Consett?
In Consett, a double-storey extension typically costs £1,500–£2,250 per m² of floor area (both floors), including VAT at 20% (standard rate). For a typical 36 m² project that is roughly £54,000–£81,000. The guide for Consett reflects typical costs in the North East, roughly 10% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (25 m²) | £37,500–£56,000 |
| Typical project (36 m²) | £54,000–£81,000 |
| Larger project (50 m²) | £75,000–£112,500 |
| Rate per m² | £1,500–£2,250 |
The biggest cost drivers are:
- Roof design and how it joins the existing roof
- Total floor area across both floors
- Bathrooms or en-suites on the first floor
- Steel beams where walls are opened up
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a double-storey extension in Consett?
Approvals for a double-storey extension in Consett 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
Handled as part of most double-storey extensions:
- Building control sign-off
- Foundations, drainage and scaffolding
- Electrics, heating, plumbing and plastering
- Brick or block walls, floors and a roof tied into the house
- Opening up at both levels with steel beams
- Windows, doors and staircase alterations
How long does it take?
Expect 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 Consett
Across the North East, colliery-era terraces and newer estates sit side by side, so the right project depends on the house type.
From DH8 outwards, we take on projects throughout Consett and the surrounding parts of County Durham.
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 handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about double-storey extensions in Consett
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.
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.
Do you build double-storey extensions in Consett?
Yes. We build double-storey extensions across Consett, including postcodes DH8. Every project starts with a free home visit.
How much does a double-storey extension cost in Consett?
In Consett, a double-storey extension typically costs £1,500–£2,250 per m² of floor area (both floors), including VAT at 20% (standard rate). A typical 36 m² project comes to roughly £54,000–£81,000. Your fixed price depends on the survey and drawings.
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.
