Covering East Grinstead
Alongside East Grinstead, we also cover Horley, Crawley (8 miles to the west) and Crowborough.
Homes in the South East
Many South East homes are inter-war or post-war semis and detached houses with room for rear and side extensions, while historic town centres and villages bring conservation area and listed building controls.
What is a side return extension?
A side return extension builds over the narrow passage that runs beside the back of many Victorian and Edwardian terraced houses, widening the kitchen or dining room by a metre or two. It is usually combined with a glazed or part-glazed roof so the deeper room still gets daylight.
- Party wall notices and surveyor liaison
- Drainage and new gully positions
- Underfloor heating ready screed if wanted
How much should I budget for a side return extension?
Indicative costs for side return extensions. London and the South East usually sit towards the top of each range.
| 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 East Grinstead
Projects in England go through two separate checks. Planning (or confirmation that the work is permitted development) comes from the district, borough or unitary council, and building regulations approval comes from the council’s building control team or a registered building control approver. Where work touches a shared wall or digs near a neighbour’s foundations, the Party Wall etc. Act 1996 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.
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.
- Glazed roofs need careful detailing against the neighbour’s wall.
From first call to completion
- Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
- We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
- Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
Questions about a side return extension in East Grinstead
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.
Is a glazed roof too hot in summer?
Modern solar-control glass and a mix of glazed and solid roof keep it comfortable. We advise on the balance during design.
Do you work in East Grinstead?
Yes. East Grinstead is within our coverage for side return extensions, along with nearby Horley and Crawley.
Side return extensions near East Grinstead
- Side return extensions in Horley
- Side return extensions in Crawley
- Side return extensions in Crowborough
- Side return extensions in Haywards Heath
Learn more about side return extensions, or see every project we cover in East Grinstead.

