Garden rooms
Garden rooms: costs, planning and quotes
Installed prices for insulated garden rooms, including the base, electrics and contingency, worked out by a quantity surveyor.
- Typical all-in cost
- £16,500 to £41,100
- Rates checked
- November 2026
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What it costs
National baseline prices for a standard finish, including VAT. London is around 25% higher; the North and Northern Ireland lower.
Price your own project| Project | Building work | Fees | Contingency | All-in |
|---|---|---|---|---|
| Insulated garden room, 10 m² | £14,600 | £400 | £1,500 | £16,500 |
| Insulated garden room, 15 m² | £21,700 | £700 | £2,200 | £24,600 |
| Insulated garden room, 25 m² | £36,300 | £1,100 | £3,700 | £41,100 |
What affects the price
- Size and insulation standard: an all-year office needs more than a summer room
- The base: a concrete slab, or screw piles on sloping or soft ground
- Running electrics from the house, and data cabling for an office
- Glazing and doors
- Cladding and roof finish
- Access: everything may need carrying through the house
Do you need planning permission?
Check my projectThese are the rules for houses in England. Flats, listed buildings and conservation areas have tighter rules, and Wales, Scotland and Northern Ireland differ. Check with your council before you build.
- A garden room usually needs no planning permission if it is not in front of the house, is no more than 2.5m tall when within 2m of a boundary, and covers no more than half the garden.
- Using it as a bedroom or a separate home needs planning permission.
- Building regulations usually do not apply under 15 m². Between 15 and 30 m², they do not apply if the room is at least 1m from every boundary or built mainly of non-combustible materials, and has no sleeping space.
- Electrics must be installed and certified by a registered electrician.
Garden room guides
Guides for this topic are being written.
Getting quotes
How to find a good garden room supplier
A fair price starts with comparing the same job across several firms.
- Ask for three quotes from the same drawings. Without a shared specification, each firm prices a different job.
- Check each firm before you invite it. Look it up at Companies House, ask to see its insurance certificate, and speak to a recent customer. TrustMark, the government-endorsed scheme, lists registered firms.
- Compare what is included, not just the total. Our quote checker shows how a quote compares with our estimate and what it leaves out.