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 Peterlee?
In Peterlee, 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. That range is adjusted for the North East, where domestic building work typically costs around 10% below the national average. 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 main things that change the cost:
- Total floor area across both floors
- Scaffolding and access to the rear
- Roof design and how it joins the existing roof
- Brick matching and external finishes
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 Peterlee?
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.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
The work we manage on a double-storey extension:
- Brick or block walls, floors and a roof tied into the house
- Windows, doors and staircase alterations
- Building control sign-off
- Design drawings and planning application
- Structural engineer’s calculations
- Electrics, heating, plumbing and plastering
How long does it take?
The build itself usually takes 14 to 20 weeks on site, after planning and building control approval. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Peterlee
Across the North East, colliery-era terraces and newer estates sit side by side, so the right project depends on the house type.
We work across Peterlee and neighbouring areas such as Seaham, Hartlepool and Houghton-Le-Spring. Postcodes we cover in Peterlee include SR8.
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
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about double-storey extensions in Peterlee
Who approves a double-storey extension in Peterlee?
Planning matters in Peterlee go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How much does a double-storey extension cost in Peterlee?
In Peterlee, 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.
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.
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.