Cost of Single Storey Extension in Crawley (2026)
If you're looking at single storey extension in Crawley right now, you should be seeing quotes in the £2,015 to £3,585 range per m². That's based on current West Sussex contractor rates and the wider UK market. Anything well outside those numbers is worth questioning before you sign.
About single storey extension in Crawley
Crawley is a medium town of around 112,000 in West Sussex. The housing is mostly period cottages, Edwardian villas and 1930s semi-detached housing alongside newer commuter developments. That matters: older properties usually mean more pipework, rewiring and retrofit surprises, while newer builds in districts like RH10, RH11 tend to be quicker jobs with standardised fittings. Local trade prices sit a little above the UK average, which tracks with West Sussex labour and material costs.
A lot of South East firms work both London and local jobs. Rates usually track London with a small discount, so you're rarely getting a bargain. Peak season runs May to September and good tradespeople can be three to four weeks out. Out of season is the time to price round.
Building jobs are labour-heavy, and materials have moved fast — brick, timber, steel, insulation and board are all 20 to 40 percent up on pre-2022. FMB and TrustMark are your best signposts for a proper builder. On anything bigger than a loft conversion, get a Building Control officer involved from day one; fixing non-compliance later costs a fortune.
Single Storey Extension cost breakdown in Crawley
Simple rear extension with standard finish
Open-plan kitchen extension with bi-fold doors
Wrap-around or glazed extension with lantern roof and structural steels
What affects the price of single storey extension in Crawley?
- Ground conditions and foundation depth
- Glazing ratio (bi-folds, roof lights)
- Kitchen refit included
- Structural steels and knock-through
- Planning permission vs PD
Crawley vs the UK average
Crawley sits in the building & construction market at a cost multiplier of 1.12× the UK national average. That puts Crawley single storey extension prices at £2,015–£3,585 versus the UK average of £1,800–£3,200 per m².
Single Storey Extension cost calculator — Crawley
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What's typically included in a single storey extension quote
- Foundations and drainage
- Brick and block shell
- Roof and glazing
- First and second fix
- Plaster and decoration
Frequently asked questions
How much does single storey extension cost in Crawley?
Budget £2,015 to £3,585 per m² for single storey extension in Crawley. Prices here are around 12% more expensive than the UK average. What moves a quote inside that range is mostly building contractor day rates in West Sussex and the specific material list for your job.
How long does single storey extension take in Crawley?
A straightforward single storey extension job in Crawley runs to 10–16 weeks. You can lose days to things outside the contractor's control — parts on backorder, awkward access, or a firm slotting your job around existing bookings. Ask for a start date and expected finish up front.
What's included in the price of single storey extension in Crawley?
A proper single storey extension quote in Crawley should cover: Foundations and drainage; Brick and block shell; Roof and glazing; First and second fix; Plaster and decoration. If any of those aren't itemised on your quote, push back and ask. A written guarantee with a clear warranty period is reasonable to expect on this kind of work.
Is single storey extension cheaper in Crawley than the UK average?
Single Storey Extension in Crawley runs around 12% more expensive than the UK average. The UK-wide benchmark for this job is £1,800 to £3,200 per m²; Crawley quotes tend to land between £2,015 and £3,585. Handy to know what the average actually looks like before you price round.
Do I need planning permission for single storey extension in Crawley?
Most rear extensions fall under Permitted Development (up to 6m terraced/8m detached with Prior Approval). Side extensions and Article 4 areas require full planning. If the property sits in a conservation area or is listed, ring West Sussex Council before you book anything in. It's a free call and saves a world of grief later.
See all single storey extension prices across the UK or browse all tradespeople costs in Crawley.