Double-storey extensions in Chorley

Covering Chorley

Chorley is about 9 miles south-east of Preston. We also cover Leyland (4 miles to the north-west), Darwen and Wigan.

Homes in the North West

The North West has long rows of Victorian terraced houses in its towns and cities, alongside inter-war semis and post-war estates, so rear extensions, dormer lofts and kitchen extensions are common projects.

What do you get with a double-storey extension?

A double-storey extension adds new rooms on both the ground and first floor in one build, typically a larger kitchen or living space downstairs and an extra bedroom or bathroom above. Because the roof and foundations are shared, the cost per square metre is usually lower than a single-storey extension.

Structural engineer’s design and calculations
Windows, insulation, plastering, electrics and plumbing
Joining the new first floor to the existing landing

How much should I budget for a double-storey extension?

Use these ranges to budget for double-storey extensions; the survey turns them into a fixed price for the agreed specification.

Double-storey extensions	Guide price incl. VAT
Standard specification	£2,400 to £2,900 per m²
Good specification	£2,900 to £3,400 per m²
High specification	£3,400 to £3,850 per m²

How is a double-storey extension approved in Chorley?

English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.

Two-storey rear extensions can sometimes be permitted development in England (no more than 3 m deep, at least 7 m from the rear boundary, roof pitch to match), but most two-storey and all two-storey side extensions need householder planning permission. Expect around eight weeks for a decision once the application is validated.

What can change the price or programme?

Neighbours’ light is assessed using the 45-degree guide many councils use.
The new roof is tied into the old one, so roof tiles and ridge details need to match.

From first call to completion

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
Construction and completion. One site lead co-ordinates every trade through to the building control certificate.

Double-storey extensions: common questions

Does a two-storey extension need planning permission?

Usually yes. In England some two-storey rear extensions are permitted development, but side extensions over one storey always need planning permission.

Is a two-storey extension better value than a single-storey one?

Per square metre, usually yes, because the foundations and roof serve two floors of space.

How do I get a price for double-storey extensions in Chorley?

Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.

Also covering

Learn more about double-storey extensions, or see every project we cover in Chorley.