No-fluff cost breakdowns and comparisons to help you spec the right garden building.
A typical UK garden office costs £21,600 – £36,000 fully installed in 2026, including foundations and VAT. Compact builds start around £15,000, while large premium pods with a bathroom and bespoke glazing can exceed £69,600.
Garden rooms cost £1,550–£2,450/m² fully installed; brick extensions run £2,500–£4,500/m² before VAT. Garden rooms win on speed, cost and minimal disruption — extensions win on long-term resale value and integrated indoor space.
Insulated garden rooms start around £8,000–£15,000 fully installed in 2026. Below that, you're looking at uninsulated summer houses or DIY kits.
Adding a bathroom to a garden office adds £4,000–£10,000 to the build, depending on whether you tap into existing drains or need a Saniflo / pumped system.