Cost of Single Storey Extension in Islington (2026)
Islington quotes for single storey extension are landing between £2,375 and £4,225 per m² at the moment. Most jobs take 10–16 weeks. The three things that move the price most around Greater London are ground conditions and foundation depth; glazing ratio (bi-folds, roof lights); kitchen refit included.
About single storey extension in Islington
Islington is a large city of around 239,000 in Greater London. The housing is mostly North London housing stock runs from Georgian and Victorian villas to 1930s semi-detached. That matters: older properties usually mean more pipework, rewiring and retrofit surprises, while newer builds in districts like N1, N5, N7 tend to be quicker jobs with standardised fittings. Local trade prices sit on the expensive side for UK trade work. That's mostly wage levels plus the cost of running a van and a yard in and around Greater London.
London's the deepest trade market in the country, and also the priciest. ULEZ, congestion charge, parking permits, higher van insurance — it all feeds into the day rate. Most decent firms charge a callout and central boroughs run a clear premium over zones 4 and 5. Book two to three weeks ahead if you can.
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 Islington
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 Islington?
- Ground conditions and foundation depth
- Glazing ratio (bi-folds, roof lights)
- Kitchen refit included
- Structural steels and knock-through
- Planning permission vs PD
Islington vs the UK average
Islington sits in the building & construction market at a cost multiplier of 1.32× the UK national average. That puts Islington single storey extension prices at £2,375–£4,225 versus the UK average of £1,800–£3,200 per m².
Single Storey Extension cost calculator — Islington
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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 Islington?
Budget £2,375 to £4,225 per m² for single storey extension in Islington. Prices here are around 32% more expensive than the UK average. What moves a quote inside that range is mostly building contractor day rates in Greater London and the specific material list for your job.
How long does single storey extension take in Islington?
A straightforward single storey extension job in Islington 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 Islington?
A proper single storey extension quote in Islington 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 Islington than the UK average?
Single Storey Extension in Islington runs around 32% more expensive than the UK average. The UK-wide benchmark for this job is £1,800 to £3,200 per m²; Islington quotes tend to land between £2,375 and £4,225. Handy to know what the average actually looks like before you price round.
Do I need planning permission for single storey extension in Islington?
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 Greater London 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 Islington.