How Much Does a Garden Room Cost in London and Surrey in 2026?
In 2026, a premium, fully insulated garden room in London and Surrey typically starts from around £21,460 + VAT for a smaller fully customised space, with larger and more complex projects increasing according to size, specification, glazing, ground conditions, services and internal finishes.
If you are considering a garden room, one of the first questions you are likely to ask is: how much does a garden room cost?
The answer depends on far more than simply the size of the building.
The structure, foundations, insulation, glazing, cladding, electrical specification, internal finishes and how the building will be used can all have a significant impact on the final cost.
For homeowners in London, Surrey and the surrounding Home Counties, a professionally designed and installed garden room can range from around £20,000 for a smaller space to £50,000, £75,000 or considerably more for a larger, highly specified building with features such as bathrooms, kitchens, extensive glazing or complex architectural detailing.
At InFrame Garden Rooms, our approach is different from a simple garden office or gym. Every building is individually designed around the client’s requirements and constructed using our precision engineered steel frame system.
How much does an InFrame garden room cost?
We believe garden room pricing should be transparent, which is why we provide example prices rather than asking clients to guess what their budget needs to be.
Our current price guide provides starting points for a number of popular sizes and specifications, with full installation and a high level of specification included.
As an indication:
Smaller 3.1 x 3.1 garden room
From approximately £21,500 + VAT
4m x 6m garden room
Approximately £30,190 + VAT, depending on the final specification and site requirements.
Larger bespoke garden rooms
Larger buildings are individually priced according to their dimensions, glazing, internal layout, finishes and services.
Luxury annexes and highly specified buildings
These can be considerably more expensive, particularly where bathrooms, kitchens, bedrooms, extensive glazing and additional plumbing or electrical requirements are included.
These figures are intended as a starting point rather than a fixed price list. Every garden is different, and a proper quotation needs to take the site and the specification into account.
What is included in the price of a garden room?
One of the most important things to establish when comparing garden room prices is exactly what is included.
A headline price can look attractive until you discover that foundations, electrics, flooring, plastering or internal painting are additional costs.
At InFrame, our standard specification includes a number of important elements as part of the building itself, including:
• Screw pile foundation system
• Precision engineered steel frame walls, floor and roof
• High quality insulation
• Double glazed doors and windows
• Electrical pack
• EPDM roofing system
• Recessed plug sockets
• Plastering
• Interior painting
• Composite Cladding
• Karndean flooring
• Thermostatic smart heating
The exact specification can then be tailored to the project, with options for premium cladding, different flooring, bifold doors, air conditioning, bathrooms, kitchens, upgraded lighting and other features.
This is why comparing garden rooms purely on the advertised starting price can be misleading.
Two buildings of exactly the same size can have very different prices because they may be constructed to very different specifications.
What affects the cost of a garden room?
1. The size of the building
The larger the building, the more materials, insulation, glazing, flooring and installation work are required.
However, size is only one part of the calculation.
A smaller building with extensive glazing, a bathroom, premium finishes and bespoke detailing can cost more than a larger, simpler garden office.
This is why we do not recommend choosing a garden room based solely on a price per square metre.
2. The construction system
The structural system is one of the most important decisions you will make.
At InFrame, the building starts with a precision engineered steel frame. Steel provides a strong, stable structural core and allows us to create bespoke layouts, large openings and generous areas of glazing while maintaining the structural integrity of the building.
Our steel frame system is designed for long term stability and is backed by a 25 year steel frame guarantee.
The frame is not simply a hidden component. It is the foundation of the entire building.
3. The foundations
A garden room needs a suitable foundation system, and the right solution depends on the site.
We use screw pile foundations as standard for our garden rooms. They can be installed quickly with considerably less excavation than traditional concrete foundations and are particularly useful where access is restricted, the garden is sloping or there are trees and established planting to consider.
Our screw pile system also provides a stable base for the steel frame across the footprint of the building.
The final foundation design is determined following a site survey.
4. The amount of glazing
Large areas of glass can transform a garden room.
Bifold doors, sliding doors, corner glazing and large picture windows can bring considerably more natural light into the building and create a much stronger connection between the interior and garden.
They can also increase the cost of the project.
For example, a simple garden office with one door and a standard window will have a very different glazing specification from an architectural garden room with an entire glazed elevation and corner opening.
5. Insulation and year round use
If you intend to use your garden room throughout the year, insulation should not be treated as an optional extra.
Our buildings are insulated across the walls, floor and roof to create a comfortable environment throughout the seasons. Our insulation specification also incorporates high performance mineral wool, which provides thermal and acoustic performance and is non combustible.
A garden room designed for daily use as a home office, gym, studio or living space needs a very different specification from a building intended for occasional summer use.
Why can two garden room quotes be so different?
If you are currently comparing quotations from different garden room companies, you may find that the prices vary considerably.
This does not necessarily mean that one company is simply more expensive than another.
The specifications may be completely different.
Before comparing prices, ask:
What is the building constructed from?
Is it timber, SIPs or steel? What is the structural specification?
What foundations are included?
Are foundations included in the quoted price, and what type of foundation system is being used?
What insulation is included?
Look at the walls, floor and roof rather than simply being told that the building is insulated.
What glazing is included?
Check the number and size of windows and doors and the specification of the glazing.
What is included internally?
Check whether plastering, painting, flooring, sockets and lighting are included.
What is included externally?
Look at the cladding, roof and any decking or external features.
Who is actually installing the building?
Ask whether the installation is carried out by the company’s own team or subcontractors.
What guarantees are provided?
Look carefully at what the guarantee covers and for how long.
These questions can make it much easier to compare quotations on a like for like basis.
Is a garden room cheaper than a house extension?
Yes. A garden room is generally considerably cheaper than a traditional house extension, while also offering the advantage of significantly less disruption to your home and everyday life.
A house extension involves altering the existing structure of your property, which can mean extensive building work, longer construction periods, disruption inside the home and potentially significant additional costs for foundations, structural alterations, roofing and internal works.
A garden room is constructed separately within your garden, meaning the work can take place largely away from your main living space. This allows you to gain substantial additional usable space without the upheaval associated with extending the house itself.
Expert Advice
Looking to the future
InFrame specialises in premium steel frame garden rooms across London, Surrey and the surrounding Home Counties.
Our buildings are individually designed and constructed around the requirements of each client.
Rather than supplying a standard garden pod, we manage the project from design through to installation, with an in house team working across the different stages of the build.
Our steel first approach provides the structural foundation for a garden room designed to offer strength, stability and long term performance, while our range of glazing, cladding and internal finishes allows every building to be tailored to its surroundings and intended use.
We believe the price of a garden room should be clear, but we also believe that price should always be considered alongside what you are actually receiving.
A garden room is a significant investment in your home. The objective should not simply be to find the cheapest building, but to understand exactly what you are buying and make sure the specification is right for the way you intend to use it.
