How much does a garden room cost?

Garden room companies price in a similar way. There is a fixed cost that every room carries whatever its size, covering the doors and glazing, the electrics, the installation team’s time and, often, the base. On top of that is a rate for each square metre of floor, wall and roof.

Across the 42 companies in our survey, the fixed part is typically around £12,400 and the rate around £900 per square metre. A room twice the size therefore costs well under twice as much, and the price per square metre falls as the room gets bigger.

A bespoke garden room is designed for one garden and one brief rather than chosen from a range. The design work, the one-off detailing and the services that bespoke rooms often include (a shower room, a kitchen, air conditioning, groundworks on a difficult site) all show in the price.

Bespoke rooms of 18–50sqm, from builders’ published examples and the project costs they have shared with the guide, mostly come to £2,200–£3,300 per square metre including VAT. Premium builders’ projects sit at £3,000–£3,200, and most of those include a kitchenette, a shower room or a full annexe fit-out. For comparison, a typical standard-range room of 20sqm is about £1,500 per square metre. Small rooms go higher per square metre: published examples of 5–12sqm bespoke rooms run from about £2,400 to £4,900. At those rates, a large bespoke garden room or annexe of 45–50sqm comes to around £100,000 or more, and fully fitted buildings reach £150,000.

Not every company that calls its work bespoke prices this way. Some publish bespoke rates of £1,500–£2,100 per square metre, much closer to a standard range, so it is worth asking what a quote includes rather than going by the word.

When comparing two quotes, the first thing to check is not the price but the scope. One company’s figure may include the base, the electrical connection to the house and a heater; another’s may stop at a building ready to be connected. The difference can easily be £3,000 to £6,000.

A growing number of companies also sell the weathertight shell on its own, with the base, insulation, electrics and interior as options. That can make a headline price look low, so check which of the items above a shell price leaves out.

Adding a shower room or toilet is the biggest single change to a garden room’s cost, because it needs a water supply and waste connection as well as the room itself. It can also change the planning and Building Regulations position.

There is no fair typical figure for this, because most of the cost sits outside the room. It depends on how far the room is from the house’s drains, whether the ground falls the right way for the waste to run by gravity or a pump is needed, and how much digging the run involves. Companies usually price it after a site visit, so ask for the plumbing and drainage to be quoted as a separate line. Garden rooms with a shower room covers it in detail.

Buying a kit is much cheaper at the outset. A self-build timber cabin of about 3m × 3m costs around £3,600–£5,400, against a typical £19,700 for a specialist-built room of the same size. The kit price usually leaves out the installation, the electrics, an interior lining and the base, which you buy separately. A plastic or steel base grid, from about £300–£900, suits only these lightweight interlocking cabins. An insulated, multi-layer garden room is far too heavy for one and needs ground screws, concrete pads or a slab.

Adding what retailers publish brings the gap closer. An insulated log cabin with its insulation kit, installation and a fitted base comes to about £11,300 at 3m × 3m, still without electrics. It also has far less insulation: typically 15–25mm, against 100mm or more in a specialist room. A buyer comparing the two is comparing different buildings, not the same building at different prices.

Insulated panel kits close that gap on the building itself. With 75–100mm of insulation in the walls, they cost around £8,800–£13,000 at 3m × 3m. The saving is in the labour: with its electrics pack and assembled for you, a 4m × 3m panel kit comes to about £17,000–£20,000 before the base and the connection to the house, against a typical £22,200 installed. Cheap garden rooms sets out the figures at three sizes.

Second-hand garden rooms come up through private sales and through the companies themselves. A panel or modular room can be taken down and rebuilt, but the base, the move and the electrical reconnection all have to be paid for again, so compare the total with a new room’s price, not the asking price alone.

Ex-display rooms are show-site buildings sold off when a company changes its range or refreshes a show site. They are usually reduced and sold by the company that built them, which can take the room down and rebuild it in your garden. Ask what the price includes: dismantling, delivery, a new base and the connection to the house. Second-hand and ex-display garden rooms covers where to find them and what to check.

Paying monthly. Several garden room companies offer finance through a lender, so the cost can be spread over monthly payments. Garden room finance lists the companies that offer it and what to look at besides the monthly figure.

Most garden rooms don’t. They are built under Permitted Development, which in most cases means a single-storey room, no taller than 2.5m if it is within 2m of a boundary, that together with other outbuildings and extensions covers no more than half the land around the original house, and is not used as a bedroom or self-contained home. Listed buildings, flats and some protected areas have tighter rules. Garden room Permitted Development explains the limits, and the garden bedroom guide covers sleeping in one. Planning fees only arise where a room falls outside these limits.

Above 30sqm of floor area, a garden room needs Building Regulations approval. Between 15sqm and 30sqm it stays exempt only if it is at least a metre from every boundary or built mainly from non-combustible materials, and at any size a room with sleeping accommodation needs approval. Garden rooms and Building Regulations explains the rules. Fewer companies publish prices at this size, and the calculator’s range is less reliable above about 30sqm. Larger rooms built for sleeping in are covered under garden annexes.

Building Regulations change the specification as well as the paperwork. Insulation, structure and fire safety all have to meet the regulations, and building control has to approve the work. One builder that prices rooms on both sides of the line charges about 20% more above 30sqm than its smaller designs would suggest: its 8m × 4m room (32sqm) costs £45,000–£47,000, against £33,000–£34,000 for 7m × 4m (28sqm). Most companies don’t publish prices above 30sqm, so for a room this size, check that the quote is for a building that meets the regulations.

Not this year. Matching the same rooms from the same companies between April and October 2026, published prices were unchanged, with one exception: one company’s pitched-roof range rose by about 12%. Its other ranges did not change. The guide re-checks prices every quarter and will report any change here.

The figures on this page come from the published price lists and online configurators of 42 UK garden room companies, checked in October 2026. They cover insulated rooms built for year-round use and installed by the company, with VAT included. Uninsulated summerhouses, sheds, DIY kits and annexes are left out.

For each company, the guide works out how its price rises with floor area, then compares every company at the same size. Each company counts once, however many ranges it sells, so one company with a long price list does not outweigh the others. The typical price is the middle of the range; the lower and upper ends show where the cheapest and most expensive tenth of companies sit.

Many garden room companies don’t publish prices at all, and quote for each project instead. That is especially true of bespoke builders, so the survey leans towards companies with standard ranges and size grids. The bespoke figures on this page come separately, from bespoke builders’ published examples and the project costs they have shared with the guide.

These are published starting prices for a standard specification, not quotes. Your own price will depend on the site, access and the options you choose.