Garden Room Costs: what you can expect to pay

Types of Garden Rooms

DIY and SIP Garden Rooms

Standard Design Garden Rooms

Bespoke Design Garden Rooms

What affects garden room costs?​

Raw Materials​

Planning Fees​

Architectural and Design Fees​

Delivery and Installation costs​

Landscaping and Levelling costs​

Utility Connection​


Garden Room Costs: what you can expect to pay

The average price of a 3m x 3m garden room can cost approximately £15,000-£25,000 depending on the size and finishes you choose.  

Types of Garden Rooms

An important factor when comparing garden room costs is the type and style of the garden room. 

DIY and SIP Garden Rooms

Self-build garden rooms like those from Dunster House are often the cheapest option and appealing for those on a budget. For example, Dunster House’s Helena W4.5m x D2.5m garden room costs just £8,459 or £861m2. This type of garden room is shipped directly to you, often in SIPs (Structural Insulated Panels), for you to erect yourself. This can represent a significant saving in labour costs. However, you must be confident that you will be able to complete the construction yourself. You will also have to consider the cost of installing foundations if your chosen model requires them. These garden rooms often lack any kind of guarantee and cheaper models will generally come with lower-quality materials and features.

Standard Design Garden Rooms

Some companies, like Little Green Rooms, supply garden rooms in a set of standard designs and finishes with delivery and installation included. At Little Green Rooms, garden room costs start from £13,950 and installation typically takes 2-3 days. The benefit of this type of garden room is you can be confident in the finished product. The building also often comes with a 10 year guarantee. The main downside of this approach is that prices are often higher than DIY models and they lack the versatility of 100% custom designs.

Bespoke Design Garden Rooms

This type of garden room offers you the most flexibility and choice when it comes to design and quality, however, it is normally by far the most expensive option. Bespoke garden rooms not only include construction and installation costs but include design fees which will contribute greatly to the overall garden room cost. Because the design is fully unique it lacks the cost advantages that come with the material economies of scale you get with standard models. Prices for a W3m x D3m custom garden room can easily exceed £20,000-£25,000.

What affects garden room costs?

Raw Materials

Raw materials make up the largest proportion of the cost of a garden room. These include things like cladding, windows and doors, flooring, timber/aluminium frame, insulation, roofing membrane, internal electrics, lights, and sockets. The higher the quality the more these materials will cost. Pine cladding will cost more than oak cladding. Double-glazed windows cost more than single-pane windows.

Planning Fees

As of 2022, a planning application costs £206 to submit. However, the good news is most garden rooms fall within permitted development rights so do not require planning permission. That said, it is important to remember that there are some exceptions to this rule. Examples include: if your garden is within a conservation site; if your garden room is more than 2.5m tall; or if you intend to sleep in your garden room. To learn more about garden rooms and planning permission, read our blog here or contact us today.

Architectural and Design Fees

Architectural fees only apply to bespoke garden rooms. They may be incorporated into the final price or quoted separately. According to Check a Trade, you can expect an architect to charge an hourly rate in the region of £50 to £100 per hour. The time taken will vary depending on the size and complexity of your chosen project. 

Delivery and Installation costs

Cost can vary depending on your location and the company you source your garden room from. Little Green Rooms offers free installation on all projects within a 20 miles radius of their Bristol workshop. Pricing is based on mileage and if the installation team needs to stay in accommodation overnight during the build. To reduce cost it may be wise to work with local companies over those further away from your home.

Landscaping and Levelling costs

In some cases, the land around the garden room will need levelling to accommodate the foundations. This will likely require the use of a small excavator, a trained operator and a soil removal service. This could be a significant hidden cost so it’s worth confirming with your garden room supplier if landscaping is required. Some companies like Little Green Rooms use ground screw piles to secure their garden rooms without the need for foundations.

Utility Connection

If you intend to use your garden room as an office then it will probably need electricity and an internet connection. The total cost will depend on your chosen supplier and the complexity of the project. If the garden room is far away from the house or there is a major obstruction then this could add additional costs when installing the cabling.


Overall garden room costs can vary greatly depending on your chosen model, size and finishes. It’s important to decide early on what style, size and level of quality you wish to achieve with your garden room project. Shopping around and comparing prices from multiple suppliers is highly recommended. 

Little Green Rooms supplies garden offices in a set of standard sizes and finishes. For more information get in touch today or download our brochure.