Garden room prices in the UK vary widely with size, specification and who builds it. As a rough guide, a small budget room starts around £6,000 to £10,000, a typical insulated mid-range office sits around £12,000 to £20,000, and larger or high-spec rooms with bathrooms or premium cladding run £20,000 to £40,000 or more. The biggest drivers are floor area, insulation and glazing, the base, electrics, and whether you need plumbing.
Work out your own estimate
Rather than rely on a single average, use our free calculator to price a room to your own size and spec, then adjust the rate for your area and finish.
Open the Garden Room Cost Calculator
What changes the price
- Size: cost scales with floor area; most home offices are 10 to 20 m2.
- Insulation and glazing: a fully insulated, double-glazed room for year-round use costs more than a summerhouse but is usually worth it.
- Base: a level, accessible site is cheaper; ground screws or a concrete pad add cost.
- Services: electrics are standard; adding plumbing for a kitchenette or shower room raises the price.
- Cladding and roof: cedar, composite and green roofs cost more than standard finishes.
Planning permission
Many garden rooms fall under permitted development, but not all. Check with our planning permission checker before you commit.
Compare local builders in our garden room directory.