How Much Does a House Extension Cost in Lincolnshire? (2026 Guide)
A realistic, no-nonsense breakdown of what an extension costs in Lincolnshire in 2026 — and what actually moves the price up or down.
PhotoIt’s the first question almost everyone asks us, and it’s a fair one. The honest answer is “it depends” — but that’s not very helpful when you’re trying to budget, so here are some real Lincolnshire figures to work from.
The rough numbers
As a guide, a single-storey extension in Lincolnshire usually works out around £1,800–£2,800 per m². So a typical 20m² rear extension lands somewhere around £40,000–£70,000. A two-storey extension often costs a little less per square metre, because you’re getting two floors out of the same foundations and roof.
Those figures include the build itself. Don’t forget to allow for VAT (most extension work is standard-rated at 20%), plus drawings, structural calculations and any planning fees.
What pushes the price up or down
- Size and storeys — the obvious one, though two-storey is more efficient per m².
- Groundworks — tricky access, sloping plots or deep foundations add cost before you even see a wall.
- Glazing — bifolds, roof lanterns and big sliding doors look stunning but aren’t cheap.
- Kitchens and bathrooms — fit-out spec can swing the budget by tens of thousands.
- Finish level — standard vs high-end materials throughout.
How to keep control of the budget
The biggest cause of overspend is changing your mind mid-build. Nail the design down early, get a clear itemised quote, and keep a sensible contingency (we usually suggest around 10%) for the things you can’t see until you start digging.
Every project is different, so the only way to a real number is a proper look at your home. We offer a free site visit and a clear, itemised written quote — no obligation.
We handle home extensions across Sleaford, Lincoln, Grantham and the wider Lincolnshire area — see our services →
