Double-storey extensions in Lancashire

Covering Lancashire

Our double-storey extensions service in Lancashire covers Preston, Burnley, Blackburn and Blackpool and more.

Homes in the North West

Across the North West, Victorian terraces, inter-war semis and modern estates all feature, and brick or stone matching is chosen to suit each street.

What goes into 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.

Measured survey, design and planning drawings
Structural engineer’s design and calculations
Windows, insulation, plastering, electrics and plumbing

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

Guide prices for double-storey extensions, including VAT where it applies. Your fixed price is confirmed in writing after the survey.

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

Do you need permission for a double-storey extension in Lancashire?

In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it applies.

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 affect a double-storey extension?

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.
Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
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.

Your questions answered

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.

How long does a two-storey extension take?

Around 14 to 24 weeks on site, plus the planning period before that.

Who deals with the council for a project in Lancashire?

We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.

Other towns nearby

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