Cost guides · 5 min read
How much does a garden room cost?
A garden room is the quickest way to add a genuinely useful room, a home office, studio or gym, without touching the house. But there is a huge gap between a glorified shed and a proper insulated building you can work in on a January morning. Here is what the real thing costs in our area.
Typical garden room costs
| Garden room | Indicative cost (2026) |
|---|---|
| Compact office (~9 m²), insulated, wired and heated | £15,000 to £22,000 |
| Mid-size room (~15 m²) with quality glazing | £22,000 to £30,000 |
| Large studio or annexe-style room with shower room or kitchenette | £30,000 to £40,000+ |
Those figures are for a building on proper foundations with insulated floor, walls and roof, double glazing, electrics on their own circuit and heating. That is what makes it usable all year and durable for decades.
Where the money goes
- Foundations: a concrete base or ground screws sized to your ground, not left to chance.
- Insulation and airtightness: the difference between a real room and a summer house.
- Glazing: aluminium sliders or bi-folds lift both the look and the cost.
- Electrics: armoured cable from the house, sockets, lighting and data, safely certified.
- Plumbing: adding a WC, shower room or kitchenette adds drainage and water runs.
Do you need planning permission?
Usually not. Most garden rooms fall under permitted development if they stay single storey, within height limits (typically 2.5 metres near a boundary) and do not cover more than half the garden. Conservation areas and listed settings are stricter, and a room used as separate living accommodation is treated differently. We check the position for your plot and handle building control where it applies.
Frequently asked questions
Can I use a garden room all year?+
Yes, if it is built with proper insulation, glazing and heating. That is the difference between a garden room and a summer house, and it is where cheap kits fall down.
Does a garden room add value?+
A well-built garden office is a strong selling point in this area, especially with so many people working from home, and typically returns a good share of its cost in added value.
Do I need building regulations approval?+
Small detached garden rooms under 15 m² with no sleeping accommodation usually do not, larger ones sometimes do. We confirm it for your specific building.