Cost of Single Storey Extension in Penzance (2026)
Expect to pay somewhere between £1,655 and £2,945 for single storey extension in Penzance, per m². Cornwall prices are noticeably below the UK average. Get at least three written quotes before committing — it's a 10 to 15 percent swing in either direction for not much effort.
About single storey extension in Penzance
Penzance is a market town of around 21,000 in Cornwall. 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 TR18 tend to be quicker jobs with standardised fittings. Local trade prices sit below the UK average. Lower contractor overheads and shorter distances across Cornwall do most of the work.
Bristol and Bath run hot. Step outside them and into Devon, Cornwall or rural Somerset and the supply thins out fast, especially for specialist trades like heat pumps or unvented cylinders. Lead times get longer the further west you go, and most firms will add travel if you're past the nearest big town.
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 Penzance
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 Penzance?
- Ground conditions and foundation depth
- Glazing ratio (bi-folds, roof lights)
- Kitchen refit included
- Structural steels and knock-through
- Planning permission vs PD
Penzance vs the UK average
Penzance sits in the building & construction market at a cost multiplier of 0.92× the UK national average. That puts Penzance single storey extension prices at £1,655–£2,945 versus the UK average of £1,800–£3,200 per m².
Single Storey Extension cost calculator — Penzance
Estimate based on live 2025 UK trade pricing. Always get 3 written quotes before committing.
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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 Penzance?
Budget £1,655 to £2,945 per m² for single storey extension in Penzance. Prices here are around 8% cheaper than the UK average. What moves a quote inside that range is mostly building contractor day rates in Cornwall and the specific material list for your job.
How long does single storey extension take in Penzance?
A straightforward single storey extension job in Penzance 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 Penzance?
A proper single storey extension quote in Penzance 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 Penzance than the UK average?
Single Storey Extension in Penzance runs around 8% cheaper than the UK average. The UK-wide benchmark for this job is £1,800 to £3,200 per m²; Penzance quotes tend to land between £1,655 and £2,945. Handy to know what the average actually looks like before you price round.
Do I need planning permission for single storey extension in Penzance?
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 Cornwall 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 Penzance.