Cost guide
How much does a two storey extension cost?
Published per-m² rates by build quality, and what a typical two-storey extension runs in total.
A two-storey extension typically costs £1,650–£2,350 per m² depending on build quality, according to Checkatrade — so a typical 60m² two-storey extension runs roughly £108,000–£180,000. Per m², two-storey extensions are often slightly cheaper than single-storey ones because the roof and foundation cost is spread across more floor area.
Last updated 17 August 2026
| Range | ||
|---|---|---|
| Standard quality | £1,650–£2,150 | Per m² |
| Good quality | £1,830–£2,350 | Per m² |
| Excellent quality | £2,150–£3,000 | Per m² |
| Typical 60m² two-storey extension | £108,000–£180,000 | Total project |
Sources: Checkatrade (quality-tier figures updated November 2024), Checkatrade (60m² total figure, updated June 2026)
Key points
- Build quality and specification tier — fittings, finishes and glazing drive the difference between the standard and excellent bands.
- Structural complexity — adding weight on a first floor over an existing structure needs proper engineering.
- Foundation work, since a two-storey extension carries more load than a single-storey one.
- Roofing and guttering to tie into the existing roofline.
These are general published ranges, not a quote. Get an estimate based on your own project.
Start Your ProjectLooking at how much does a two storey extension cost?? See how we approach it →
Other cost guides
More published cost ranges
How much does a loft conversion cost?
Published industry ranges by conversion type, so you can budget sensibly before getting a quote.
How much does a house extension cost?
The published UK per-m² rate for a single-storey extension, and what actually moves it.
How much does a side extension cost?
Published UK ranges for a side and side-return extension.
Ready to make more of your home?
Tell us what you're thinking and let's see what's possible.
Start Your ProjectBuilt Properly. Finished Faster.