An honest guide to what a house extension really costs in Lanarkshire in 2026
How Much Does a House Extension Cost in Lanarkshire? Hamilton, Bothwell, East Kilbride and Biggar
It’s one of the first things people ask us, and most builders hum and haw rather than give a straight answer. So, to cut through the noise, here’s an honest one — from a Lanarkshire builder.
To begin with, as a rough guide in 2026, a good‑quality finished single‑storey extension in Central Scotland tends to land around £1,500 to £2,500 per square metre, depending on the spec and the job.
What that means in real money
For example:
- A small extension around 15 m² — roughly £25,000 to £40,000
- A medium one around 20–25 m² — roughly £35,000 to £55,000
- Larger or higher‑spec — more again
In short, treat these as a starting point, not a quote — every house is different, which is why we built an instant online estimator.
What drives the cost
In most cases, the main factors are size; single‑storey vs two‑storey (going up is often better value per m²); the finish and spec; ground conditions and any structural steel; whether there’s a kitchen or bathroom inside; and access to the site.
The bits people forget
On top of that, you’ve got kitchen or bathroom fit‑out, a building warrant (Scotland’s version), planning permission if your job needs it, and finishes and decoration. Put simply, a builder who leaves these out to make their number look smaller isn’t doing you a favour.
Why the cheapest quote is rarely the cheapest job
If one quote’s miles cheaper, that’s a warning — not a bargain. Usually, something’s been left out or will “grow” once you’re committed. Our way is simple: a fixed price agreed up front, and no final payment until you’re happy.
Get a price for your extension
Ultimately, the figures above are a guide; the only number that matters is the one for your house. So, use our online estimator for an instant ballpark, then we’ll come out and give you a proper fixed quote — whether you’re in Hamilton, Strathaven, Bothwell or anywhere across Lanarkshire.
Get your instant estimate at buildersoflanarkshire.com/instant‑estimator or call John on 07376 278102.
