house-extension.uk

Bedroom extensions across Lancashire

We design and build bedroom extensions for houses in Lancashire, with a written price once the survey and design are done and one point of contact throughout.

  • Guide priceFrom £24,500 inc VAT
  • PlanningUsually a householder application
  • Towns covered19
  • Site visitFree, no obligation
Bedroom in an extension with a roof window and an en-suite shower room

Bedroom extension prices in Lancashire

Prices below are for Lancashire, using the North West England factor of ×0.95. They are guide ranges including VAT for the build only, not a quote.

Typical rates in Lancashire: £1,520 to £3,040 per m² including VAT, depending on specification.

SizeEssentialStandardPremium
One bedroom
12 m²
£24,500 – £30,500£24,500 – £32,000£27,000 – £36,500
Bedroom and en-suite
18 m²
£27,000 – £33,500£32,000 – £42,000£41,000 – £55,000
Two rooms
30 m²
£45,500 – £56,000£54,000 – £70,000£68,000 – £91,500

For a figure based on your own dimensions, use our guide-price tool.

Included in a typical project

  • En-suite drainage and ventilation design
  • Fire safety: escape windows and smoke alarms to building regulations
  • Heating extended to the new rooms
  • Planning drawings and application

New bedrooms on an upper floor need an escape window or a protected route to the outside under the building regulations. We design the window sizes and stair route to meet that from the outset.

Planning rules that apply in Lancashire

In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.

The planning position for a specific Lancashire address depends on its history and any designations, which is why we check it at the first visit.

Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.

Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.

Applications are decided by the local planning authority (your district, borough or unitary council).

Local to Lancashire

Towns we cover in Lancashire include Preston, Burnley, Blackburn, Blackpool, Morecambe, Lancaster, Lytham St Annes, Skelmersdale. The North West has a high share of Victorian and Edwardian terraces with rear yards and outriggers, plus large areas of inter-war semis in the suburbs.

From first visit to completion

Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.

  1. Free site visit

    It starts with a visit to your house to measure, check access and talk through ideas and budget.

  2. Design and approvals

    Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.

  3. Fixed written price

    You receive a written, itemised price and programme. Nothing starts until you are happy with it.

  4. Build and sign-off

    The build is managed from start to finish, inspected at each stage and signed off on completion.

Your questions about a bedroom extension in Lancashire

How long does a bedroom extension take to build in Lancashire?

On site, typically 14 to 22 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.

Can I see a price before committing to anything?

Yes. The guide prices on this page are adjusted for Lancashire, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.

Do you cover all of Lancashire?

Yes, across the whole of Lancashire. Site visits are free and there is no obligation.

Will a new bedroom need planning permission?

Upstairs additions usually do. Ground-floor rooms may fall within permitted development, depending on size and position.

Does an en-suite need a window?

No, but it needs mechanical extraction that meets the building regulations. We design the duct route at the drawing stage.

Book a free site visit in Lancashire

We will measure up, check the planning position and give you honest guide figures.

  • Free, no-obligation site visit
  • Planning route checked before you spend on drawings
  • Written price once the design is agreed
  • Building control sign-off at the end

Prefer to talk? Call 0800 088 6341 or .

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