Covering Darwen
Darwen sits 11 miles south-east of Preston, with Blackburn 4 miles to the north and Accrington 6 miles to the north-east.
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 does a side return extension involve?
Side returns are small in area but heavy in detail: party walls, a glazed roof, and steelwork to take out the original back wall. We design the roof for light and drainage, agree the party wall process early, and keep the work tidy because access is often through the house.
- Party wall notices and surveyor liaison
- Structural steel to remove the side wall
- Underfloor heating ready screed if wanted
How much does a side return extension cost in Darwen?
Typical ranges for side return extensions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.
| Side return extensions | Guide price incl. VAT |
|---|---|
| Standard specification | £3,350 to £3,700 per m² |
| Good specification | £3,700 to £4,150 per m² |
| High specification | £4,150 to £4,550 per m² |
What approvals does a side return extension need in England?
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.
In England a single-storey rear extension can often go ahead under permitted development: up to 3 m deep on an attached house or 4 m on a detached one, no higher than 4 m, with eaves no higher than 3 m within 2 m of a boundary. Deeper extensions, up to 6 m or 8 m, need prior approval from the council first.
What should Darwen homeowners check first?
- Most side returns touch a shared boundary, so the Party Wall etc. Act 1996 usually applies in England and Wales.
- Glazed roofs need careful detailing against the neighbour’s wall.
From first call to completion
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- 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.
- Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.
What people ask before starting
Does a side return need planning permission?
In England it can be permitted development if it is single storey, no higher than 4 m and no wider than half the original house. Conservation areas are the main exception.
Will I need a party wall agreement?
Most likely, because the new wall usually sits on or near the boundary. We serve the notices and work with your neighbour’s surveyor if one is appointed.
How do I get a price for side return extensions in Darwen?
Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.
Side return extensions in nearby towns
- Side return extensions in Blackburn
- Side return extensions in Accrington
- Side return extensions in Chorley
- Side return extensions in Rawtenstall
Learn more about side return extensions, or see every project we cover in Darwen.

