Haslingden, Lancashire
Semi-detached rear extension in Haslingden
Single or two-storey extensions for semi-detached houses, with side access and one party wall. We design, get the approvals for and build rear extensions for semi-detached houses in Haslingden and the surrounding area, with one contract from the first survey to building control sign-off.
Haslingden sits in Lancashire, with postcode districts including BB4. Semi-detached houses are common across Lancashire, and their side access makes rear extensions quicker to build.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a semi-detached rear extension cost in Haslingden?
Guide prices for a semi-detached rear extension in Haslingden start from our North West England rate of £1,790–£2,910 per square metre, including VAT. North West prices sit below our West Midlands baseline; access on terraced streets is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £21,500–£35,000 |
| 4 m wide × 5 m deep (20 m²) | £35,500–£58,500 |
| 4 m wide × 6 m deep (24 m²) | £43,000–£70,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a semi-detached rear extension in Haslingden?
Planning for a semi-detached rear extension in Haslingden follows the English householder rules.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Haslingden like to extend?
Stone and brick terraces are common around Haslingden. Where houses back onto a ginnel or alley, deliveries can come in from the rear, which makes the build tidier.
How a semi-detached rear extension in Haslingden comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Semi-detached rear extensions near Haslingden
Close by, we work in Rawtenstall, about 1.6 miles away, and Accrington, about 3.8 miles away.
- Semi-detached rear extension in Rawtenstall
- Semi-detached rear extension in Accrington
- Semi-detached rear extension in Ramsbottom
- Semi-detached rear extension in Bacup
- Semi-detached rear extension in Darwen
Other work in Haslingden:
FAQ
Semi-detached rear extension questions in Haslingden
How much does a semi-detached rear extension cost in Haslingden?
As a guide, £1,790–£2,910 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £21,500–£35,000 at that rate. Your written price follows the survey.
Do I need planning permission for a rear extension in Haslingden?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
How far can I extend a semi without planning?
3 metres under permitted development in England, or up to 6 metres with prior approval, outside designated land.
What postcode areas do you cover around Haslingden?
Including BB4, and the surrounding Lancashire area.
How long does a rear extension take to build in Haslingden?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.