Covering Darlington
Our coverage around Darlington (DL3, DL98) also includes Newton Aycliffe, Stockton-on-Tees and Thornaby-on-Tees.
Homes in the North East
Housing across the North East ranges from colliery terraces and Tyneside flats to suburban semis and modern estates, each with different options for extending.
What is a side return extension?
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
- Glazed or solid roof with rooflights
- Drainage and new gully positions
How much does a side return extension cost in Darlington?
What side return extensions typically cost. These are guide ranges; the written quote for your house replaces them.
| 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 |
Planning and building rules in Darlington
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 can change the price or programme?
- Most side returns touch a shared boundary, so the Party Wall etc. Act 1996 usually applies in England and Wales.
- Many terraces sit in conservation areas, where side extensions need planning permission.
What are the steps?
- Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
- 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.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
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.
Do you work in Darlington?
Yes. Darlington is within our coverage for side return extensions, along with nearby Newton Aycliffe and Stockton-on-Tees.
Side return extensions in nearby towns
- Side return extensions in Newton Aycliffe
- Side return extensions in Stockton-on-Tees
- Side return extensions in Thornaby-on-Tees
- Side return extensions in Bishop Auckland
Learn more about side return extensions, or see every project we cover in Darlington.

