Side extensions for homes in Crawley
Planning a side extension in Crawley? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in CrawleyFrom £24,500 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsRH10, RH11
Guide prices for Crawley
For Crawley we adjust our national guide rates by ×1.12, the factor we use for South East England. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Crawley: £1,960 to £3,810 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £24,500 – £30,000 | £27,500 – £36,000 | £34,500 – £46,000 |
| 3 m × 6 m 18 m² | £35,000 – £42,500 | £41,000 – £53,500 | £52,000 – £69,000 |
| 3 m × 8 m 24 m² | £47,000 – £56,500 | £55,000 – £71,500 | £69,500 – £91,500 |
Try the guide-price tool to see a range for your own size and finish.
Is a side extension right for your house?
- Homes needing a utility, study or ground-floor bedroom
- Detached and semi-detached houses with side land
- Houses where the rear garden is small
Extensions in and around Crawley
Site visits are available across Crawley (RH10, RH11). We also work in nearby Horsham (7 miles), East Grinstead (8 miles), Haywards Heath (9 miles), Burgess Hill (11 miles).
Horley, in Surrey, is roughly 4 miles from Crawley and also on our list. The South East has a broad mix of 1930s semis, post-war estates, newer developments and period cottages, and many houses have enough garden for a generous rear extension.
Do I need planning permission in Crawley?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
How the project works
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
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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.
Side extension questions answered
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Crawley, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Crawley?
Yes. We cover Crawley and the surrounding parts of West Sussex. Site visits are free and there is no obligation.
Do I need building regulations approval in Crawley?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I build a side extension without planning permission?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a planning application.
Can I build over my driveway?
Yes, if the foundations work and you keep any parking the council requires. Drains and services under drives are common, so we check before design.
Book a free site visit in Crawley
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.