Garden Room Cost

How Much Does a Garden Room Cost?

The average cost of a garden room ranges from £20,000 to £38,000 (based on a standalone 12m² to 15m² size build).

However, the cost aside from the size, there are a number of other cost factors that could put your budget beyond either side of this price range.

For example, premium materials such as oak and cedar wood cladding, or installing bifold doors or a skylight will put the cost up. Alternatively, investing in a much smaller, prefabricated flat-pack will cost far less.

Here is a quick look at typical prices per square metre by quality:

It's also worth considering the desired use for your garden room, as should you require additional electrics and plumbing, to install added luxuries such as a games room or bathroom suite, this could substantially increase the final cost.

Therefore, it should be noted any prices mentioned within the guide are displayed as an average range. It's also possible that, in some cases, smaller garden rooms can actually cost more than slightly larger options.

It is also recommended to request quotes from local builders near you, as labour fees can vary throughout the UK and this can also impact how much you need to budget for your project.

Garden Room Prices

As the previous section highlights, the cost of building an outbuilding (in terms of labour and supply costs alike) can vary significantly, with size being a key factor. As a rough guide you can assume an average garden room costs between £1,700 and £2,200 per m², but here is a more detailed breakdown of the cost of building a garden room based on size:

Garden Room Costs by Size

Let’s take a look at the various sized rooms available and their costs in more detail.

Small Garden Rooms (4.5m² to 7.5m²)

Small garden rooms of between 4.5m² and 7.5m² are priced at around £14,000 to £20,000 for a 4.5m² garden room, £12,000 to £18,000 for a 6.25m² garden room or £15,000 to £25,000 in the case of a 7.5m² garden room.

While a small garden room can cost less, it’s important to consider whether it would be well-suited to your needs or not. A small garden room may prove cosy, but if it’s too small for your needs (such as if you wanted a home gym), it could end up feeling cramped and impractical and thus not a particularly great investment.

Medium Garden Rooms (9m² to 15m²)

Moving on to medium garden rooms, you can expect prices of £16,000 to £28,000 for a 9m² garden room, £20,000 to £32,000 for a 12m² garden room or £24,000 to £38,000 in the case of a 15m² garden room.

Medium garden rooms may be well-suited in some cases and could be the ideal balance between cost and space. However, as with small garden rooms, the risk still exists of a medium garden room being not quite large enough for your needs.

Large Garden Rooms (18m² to 24m²)

Lastly, looking at large garden rooms, these are priced at approximately £26,000 to £37,000 for an 18m² garden room, £28,000 to £40,000 for a 20m² garden room or between £32,000 to £50,000 should you want a 24m² garden room.

A large garden room may be just what you need. Obviously, the key downside is that large garden rooms are costlier. It’s important to carefully consider what size garden room you want to ensure either you don’t spend more than you need or end up with a garden room that is too small.

If in doubt as to how to approach this and make a sure decision, consult with a designer, architect or builder for advice.

Supply Cost of a Garden Room

The cost of having a garden room will primarily consist of the cost of labour and the cost of materials. Another part of the overall cost that may apply is waste removal expenses.

Looking at the supply-only costs, you may be looking at prices of around £70 to £90 per m² for a deck base and £50 to 90 per m² for a roof system. Windows and doors may cost between £500 and £700 each. However, these prices can swell to or around £2,000 in some cases. Ultimately, supply costs can vary quite a bit depending on the type, size and nature of the garden room you’re having installed.

Labour Cost to Build a Garden Room

Labour is another major factor to consider when budgeting for a garden room. On average, labour costs range between £300 and £400 per day, although this can vary depending on where in the UK you live.

Given that most garden rooms take approximately 1 to 3 weeks to complete, this will be represented in a total labour cost falling between £1,500 and £6,000. As such, materials costs will tend to take up the majority of your overall budget, although this can also affect the complexity of the build and potentially the time required to finish the job.

The construction process involves more than just building the structure. Contractors will also spend time preparing the site before work begins and tidying up the area once the job is finished, although in most cases this is all within the 1 to 3 timeline.

However, if substantial waste removal is needed or there's more ground preparation required than expected, this can also impact both the timescale and end cost.

Factors That Impact Garden Room Costs

There are a range of factors that go towards creating the perfect garden room, some of which will also come with the need to hire separate tradesmen, such as an electrician or plumber, either during the build or once the bulk of the garden room project has been completed.

Below we look at some of the most notable examples that can affect the overall price of your own garden room:

• Garden Room Size — Larger rooms require more in terms of materials and often longer labour or additional workman, making size a major cost factor for your garden room project.
• Design and Use — Having a complex or bespoke design with additional features may sometimes be for purely aesthetic reasons, however, they can also add a functional value to the build.
• Foundation and Site Preparation — The type of foundation, soil conditions, location, and any permits that are required can increase costs by £500-£2,500 and can impact how long the project takes.
• Materials and Insulation — Whether you're building a prefab garden room kit, log cabin or bricks and mortar, the material cost along with how you insulate your build will impact the price and energy-efficiency. A well-insulted garden room can cost £1,500-£4000 more than one with less or no insulation.
• Electrical and Plumbing Work — Costs vary depending on the extent of wiring, plumbing, heating, or cooling systems required. For example most garden rooms at least require lighting (£300-£800), while central heating and air conditioning will create further expense, £1,000+.
• Bathroom and Toilet — Following on from the above, if you're adding facilities such as an outside toilet for a garden room bar or an en suite for a guest room, this can increase the cost significantly. The cost of a garden room with a shower and toilet might be £2,000-£6,000 more than one without any plumbing.
• Windows, Doors, and Finishes — The type, size, and quality of windows, doors, and interior finishes (such as flooring, decor and furniture) will all add to the overall cost.
• Internal Features — If you want to use your room as a fully-fitted guest space or a well-equipped gym, the cost of additional equipment and furniture can be substatial. You will also have to factor in additional lighting, air conditioning, or bespoke finishes, all of which can drive up costs.

Types of Garden Rooms

There are many garden room ideas and uses to consider. Here is a breakdown of the estimated build cost of each type.

Home Office

• Best for: Remote work.
• Typical size: 9 to 12 m²

One of the more common uses for a garden room comes in the form of a home office. This can act as the perfect space to do some additional work or planning in relation to your job or even as a creative workspace.

A creative workspace might mean arts and crafts (although then you may prefer a hobby room) or creative works that are more office-oriented, such as novel writing or working on graphic design on your laptop or PC.

A home office may prove less expensive than most types of garden rooms, particularly since you can add basics such as a desk and office chair on a budget. Although you may still have to consider hidden costs such as adding electrics and a stable internet connection.

Summerhouse

• Best for: Relaxing on summer days.
• Typical size: 7.5 to 12 m²

A lot of households would love to have a garden room built to create a summerhouse. This can act as a wonderful space for you, other members of your household and visitors alike to enjoy on sunny summer days.

Summerhouses usually come with tiled or felt roofs along with various windows and glazed doors to let in plenty of sunlight.

Home Gym

• Best for: Training at home.
• Typical size: 12 to 18 m²

Some households may prefer to use their garden room as a home gym to help keep fit. A garden room can act as the ideal installation to make space for your own gym with the equipment and fixtures you want.

As previously mentioned, a home gym may prove relatively more expensive, given all the equipment you may choose to have installed.

Workshop

• Best for: DIY and storing tools.
• Typical size: 9 to 15 m²

Another common reason to have a garden room constructed is for the purpose of creating a workshop. Rather than having an entire garage extension built, garden buildings can prove more than sufficient to create a space to work or store tools, equipment and more.

Garden Bar

• Best for: Entertaining guests.
• Typical size: 9 to 15 m²

A garden bar/pub or entertainment room offers a dedicated space for socialising without taking over the main house. It can be arranged with a small bar area, seating and speakers to suit your needs.

Guest Accommodation

• Best for: Hosting visitors if you have no guest room.
• Typical size: 15 to 24 m²

Rather than transforming a spare room, another fairly popular reason to have a garden room built is to provide separate space to accommodate guests.

Since garden rooms are often less expensive than say a loft conversion, it could prove the most cost-efficient and feasible way to add space to your property for guest accommodation if you lack enough room as is.

Garden Room Materials

Garden rooms can be categorised based on the type of material they are made from. Here we’ll look at the pros and cons of various materials that can be used in the process of creating a garden room.

Glass Garden Room

• Best for: Maximum light and views.
• Cost per m²: £2,100 to £2,200

Along with there being distinct options from an insulation perspective (single, double, and triple-glazed), glass is sustainable and 100% recyclable, as well as offering a high quality and durability. What’s more, glass is transparent, as well as dust- and water-proof (as long as everything is correctly installed and sealed).

Pros

• ✔ Sustainable and 100% recyclable.
• ✔ High quality and durability.
• ✔ Transparent, dust and water-proof when correctly installed and sealed.

Cons

• ✖ Brittle (a stray football or cricket ball could easily damage it).
• ✖ Relatively expensive and requires more maintenance than many other building materials.
• ✖ Issues of glare and heat absorbent properties, so it could heat up too much on sunny days like a greenhouse.

Composite Garden Room

• Best for: Low maintenance and a modern look.
• Cost per m²: £1,700 to £1,900

Composite material consists of two or more materials being added together and is ideal for building low-cost garden rooms. Although cheaper, it's still a solid insulator. Also, thanks to these other beneficial properties, composite garden rooms are generally fairly strong and durable.

Pros

• ✔ Relatively low-costing material.
• ✔ A solid insulator.
• ✔ Generally fairly strong and durable.

Cons

• ✖ Can be relatively brittle depending on the product.
• ✖ May be at a greater risk of fire at certain temperatures, so check with manufacturer for fire rating and impact strength.

Wood Garden Room

• Best for: Natural appearance and warmth.
• Cost per m²: £1,900 to £2,000 (cedar or oak up to £2,200)

Timber is a commonly used building material. Many prefer wood for the natural look and feel it offers. Top advantages of wood as a building material include its versatility, ease of maintenance and repair and the warmth it can provide to occupants with a structure made using wood.

Pros

• ✔ Versatile.
• ✔ Easy to maintain and repair.
• ✔ Provides warmth for occupants.

Cons

• ✖ Higher fire hazard.
• ✖ Prone to rot, shrinkage and swelling.
• ✖ Can suffer damage from pests and fungi.

uPVC Garden Room

• Best for: Simplicity and less upkeep.
• Cost per m²: £1,700 to £1,900

Unplasticised polyvinyl chloride or uPVC is another standout building material. Some of the core upsides of uPVC are its durability, sound and heat insulation attributes, cost-efficiency and the facts it can be recycled and is relatively low maintenance.

Pros

• ✔ Durable.
• ✔ Offers sound and heat insulation.
• ✔ Cost-efficient and relatively low maintenance.
• ✔ Can be recycled.

Cons

• ✖ Limited design options.
• ✖ Temperature sensitivity.
• ✖ Upfront cost.
• ✖ For some households, the appearance will not be their cup of tea.

Checklist: Hiring a Garden Room Builder

When seeking a garden room contractor or building company to hire, it’s important you opt for the right tradesmen for the job.

During the final stages of the project, in order to create the perfect garden room it's also likely you'll need to hire additional contractors for some specific tasks (such as an electrician or painters and decorators).

As such, here are some key pointers to keep in mind:

• Are they suitably qualified and officially registered? Check that they hold the necessary trade qualifications, certifications, or licenses required for the work, and ask how long they've been in business.
• Are they a member of any trade associations? Find out if they belong to a recognised scheme or government-approved body, and verify with the trade association if necessary.
• Are they a limited company? Limited status can make background checks easier. Ask them to confirm whether any claims have been made against the company in the last five years to assess their track record.
• Are they fully insured? Although not a legal requirement, check for Public Liability, Contractors All Risk, Employers’ Liability, and Professional Indemnity Insurance.
• Can they self-certify their work? Ask if they can self-certify to confirm compliance with building regulations, and if they will be requesting the relevant documentation to ensure your build meets legal standards.
• Do they offer a guarantee? Request a written guarantee so you know what is covered before, during, and after the build. Insurance-backed guarantees from a UK insurer can provide extra protection if the company stops trading.
• Do they follow current health and safety standards? Ensure they follow health and fire safety procedures and are aware of planning permission and building regulation requirements.
• Do they have examples of their work? Reviewing their portfolio or customer photographs gives a clear sense of their professionalism and quality, as well as providing you with inspiration.
• Have they received positive reviews? Check feedback on their MyJobQuote profile, ask friends and family for recommendations, and review their online presence.
• Have you received more than one quote? With MyJobQuote, you can request several quotes from local builders specialising in garden buildings without any further commitment to go ahead.