Cost of Single Storey Extension in Darlington (2026)
Darlington quotes for single storey extension are landing between £1,585 and £2,815 per m² at the moment. Most jobs take 10–16 weeks. The three things that move the price most around County Durham are ground conditions and foundation depth; glazing ratio (bi-folds, roof lights); kitchen refit included.
About single storey extension in Darlington
Darlington is a medium town of around 107,000 in County Durham. The housing is mostly red-brick Victorian terraces, stone-built millworker housing and post-war semi-detached estates typical of Northern industrial towns. That matters: older properties usually mean more pipework, rewiring and retrofit surprises, while newer builds in districts like DL1, DL3 tend to be quicker jobs with standardised fittings. Local trade prices sit below the UK average. Lower contractor overheads and shorter distances across County Durham do most of the work.
Straight up, the North East is usually the cheapest region for trade work. Gas Safe engineers and electricians often quote 10 to 15 percent under the UK average. Newcastle, Durham and Middlesbrough are well served; rural Northumberland jobs tend to go to a regional firm rather than a one-van outfit.
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 Darlington
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 Darlington?
- Ground conditions and foundation depth
- Glazing ratio (bi-folds, roof lights)
- Kitchen refit included
- Structural steels and knock-through
- Planning permission vs PD
Darlington vs the UK average
Darlington sits in the building & construction market at a cost multiplier of 0.88× the UK national average. That puts Darlington single storey extension prices at £1,585–£2,815 versus the UK average of £1,800–£3,200 per m².
Single Storey Extension cost calculator — Darlington
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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 Darlington?
Budget £1,585 to £2,815 per m² for single storey extension in Darlington. Prices here are around 12% cheaper than the UK average. What moves a quote inside that range is mostly building contractor day rates in County Durham and the specific material list for your job.
How long does single storey extension take in Darlington?
A straightforward single storey extension job in Darlington 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 Darlington?
A proper single storey extension quote in Darlington 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 Darlington than the UK average?
Single Storey Extension in Darlington runs around 12% cheaper than the UK average. The UK-wide benchmark for this job is £1,800 to £3,200 per m²; Darlington quotes tend to land between £1,585 and £2,815. Handy to know what the average actually looks like before you price round.
Do I need planning permission for single storey extension in Darlington?
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 County Durham 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 Darlington.