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 Ormskirk?
In Ormskirk, 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. Building costs in the North West run about 6% below the UK average, and the figures for Ormskirk are adjusted to reflect that. 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
- Bathrooms or en-suites on the first floor
- Brick matching and external finishes
- Total floor area across both floors
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 Ormskirk?
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.
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
The work we manage on a double-storey extension:
- Structural engineer’s calculations
- Brick or block walls, floors and a roof tied into the house
- Electrics, heating, plumbing and plastering
- Design drawings and planning application
- Windows, doors and staircase alterations
- Opening up at both levels with steel beams
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 Ormskirk
Terraced streets across the North West often suit rear dormers and single-storey kitchen extensions.
Projects in Ormskirk (L39) 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
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about double-storey extensions in Ormskirk
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 Ormskirk?
Yes. We build double-storey extensions across Ormskirk, including postcodes L39. Every project starts with a free home visit.
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 Ormskirk?
In Ormskirk, 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.
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.
