Extension plans and drawings in Blackburn
We prepare extension plans and drawings for homes in Blackburn, as a stand-alone service or as the first stage of a design and build project.
- Guide price in BlackburnFrom £1,100 inc VAT
- PlanningWe find the right route for you
- Timescale2–6 weeks for drawings
- Postcode districtsBB1, BB2, BB3, BB5, BB6
What it costs in Blackburn
Guide fees for Blackburn including VAT, using our North West England factor of ×0.95. Council and building control charges are not included.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Measured survey and planning drawings | £1,100 – £2,100 |
| Standard | Planning drawings plus building regulations drawings | £2,050 – £3,650 |
| Premium | Full pack with structural calculations and 3D visuals | £3,200 – £5,250 |
Try the guide-price tool to see a range for your own size and finish.
Included in a typical project
- 3D views to check the look and the light (full pack)
- Planning drawings: existing and proposed plans and elevations, site and location plans
- Measured survey of the house and garden
- Two or three layout options to compare
- Structural calculations from an engineer (full pack)
The most expensive changes are the ones made after the steel is ordered. A good design stage settles layout, heights, glazing and services on paper, so the build price is firm.
Working in Blackburn
We cover Blackburn and the postcode districts BB1, BB2, BB3, BB5, BB6. We also work in nearby Darwen (4 miles), Accrington (5 miles), Chorley (9 miles), Rawtenstall (9 miles).
Just over the Greater Manchester border, Horwich is about 11 miles away. 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.
Will the council need to approve it?
In England the main routes are permitted development (ideally confirmed with a lawful development certificate, £274), larger home extension prior approval (£249, 42 days) and a householder planning application (£548, normally 8 weeks), with council fees as set from 1 April 2026.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
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.
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions answered
Do you cover all of Blackburn?
Yes. We cover Blackburn and the surrounding parts of Lancashire. Site visits are free and there is no obligation.
How long does this take for a Blackburn home?
2–6 weeks for drawings, depending on the council and the complexity of the project.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Blackburn, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Can I use your drawings with another builder?
Yes. Once paid for, the drawings are yours to use for your project.
Do I need an architect?
Not necessarily. For most extensions an experienced designer or architectural technologist is enough. For listed buildings or complex sites an architect’s input can help.
Book a free site visit in Blackburn
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 .
Book a free site visit
Tell us a little about the project and we will arrange a time.