How much does it cost to get a garden room?

The garden room costs in this article are correct as of 2022

Garden rooms are an increasingly popular way to add more space to your home, giving you huge flexibility whether you want the space for a garden home office, gym, workshop, cinema room or “man cave”.

Contemporary garden rooms can range from simple self-assembly units to bespoke constructions, with a price range to match:

• Simple, small wooden cabins can be purchased and installed for around £1,500. With extras like clearing and preparing the ground, the total cost may rise to around £3,000.
• Off-the-peg garden rooms made from timber frames or made up of SIPs (Structural Insulated Panels), featuring the same level of insulation as your home and similar standards of doors and windows, are more expensive.
• A small unit of around 2m x 2m may cost around £4,000. Laying foundations and connecting electricity may take this price to around £6,000.
• Bespoke garden rooms made to your exact requirements, and using features like floor to ceiling glazing, cedar cladding or bifold doors will push prices to at least five figures, typically between £12,000 and £20,000, though there is really no upper limit depending on the size of the room and your design choices.

Garden room installation costs

A key element of installing a garden room is preparing the space where it will go.

Depending on where you buy your garden room from, the cost of installing the foundations may be included in the total cost of the unit, however, in some cases you may need to hire groundworkers or landscapers to prepare the plot in advance.

Typically, garden rooms won’t require the traditional foundations used for house building. The most common method is preparing a concrete slab base. The earth will be dug out to a certain depth, then covered with a layer of hardcore, before concrete is poured over and levelled off to create a flat, solid surface which the room will sit on.

For a small concrete slab base - around 2m x 2m - it will cost around £1,500, depending on ground conditions and ease of access, with prices increasing from that based on the size.

Another popular method is to use ground screws, which are dug into the earth to the required depth, and used as a base which the frame of the room is then fitted on to. These are particularly useful where the ground isn’t level, and cause less of a longterm impact than installing a concrete base.

A ground screw system can cost around £2,000 depending on the size of the unit being installed.

Additional costs to upgrade your garden room

A simple wooden chalet-style garden room or summerhouse isn’t functionally much different from a garden shed, even if you plan to spend time in it rather than keeping the lawnmower in there.

To get maximum use out of the space, you’ll want to ensure that it’s comfortable and has all the amenities you’ll need.

Electrics

If you want to use your garden room as a garden office, garden gym or garden workshop, then you’ll almost certainly need to install electrics, both lighting, and sockets for power.

This can be added retroactively to a simple wooden garden room, but most modern garden office units will have sockets and lighting fixtures built in, meaning you’ll just need to make the connection to your home’s electrics.

Connecting it entails running an armoured cable from your home to a consumer unit in your garden room. Ideally this will run underground, meaning a trench will need to be dug out for the cable to lie in.

A qualified electrician will be needed to install the cabling and ensure it is safe. The cost of the installation will be around £600 to £1,000 for a typically sized garden.

However, the electrician will probably not dig out the trench - you may wish to do this yourself, or hire a landscaper or handyman.

Insulation

If you’re planning to spend a lot of time in your garden room, you’ll wanto to ensure it maintains a good temperature, whatever the weather. Insulation is key to this.

Higher end garden rooms made from timber frame or modular construction will feature insulation as standard, and the overall price of the unit will be affected by the quality of the insulation. Many manufacturers will aim for home-quality insulation.

It’s possible to retroactively add insulation, whether mineral wool or rigid insulation boards, to simple timber garden rooms, but they are not designed for it - it will involve adding battens and plasterboard to cover the insulation, reducing the overall size of the space.

Depending on the size of the room, it will probably cost around £1,000 for the materials and installation of wall insulation.

Windows and doors

The quality of window and door you use in your garden room will typically be an option you can choose from when picking your unit, from cheaper uPVC frames to expensive hardwoods.

However, you may also want to make a feature of the doors or windows in your garden room - making the most of the outdoor space and natural light in the garden.

Wall-to-ceiling windows that take up a whole side of the room are very popular, as are bifold doors that allow you to open the entire side of the room to bring the outside in.

These can add around £2,000 to £3,000 to the overall cost.

Kitchens and bathrooms

If you’re planning to use the space as a gym or workshop you may want to install some washing facilities.

Connecting cold water means digging a trench, as with electrics, with pipes that run from your home to the garden room. Hot water can mean fitting a small hot water tank. Both of these can cost around £500.

Fitting a fully plumbed toilet means connecting the garden room to the mains sewage. This will have to be covered by Building Regulations, so it is usually only done for the largest projects where strictly necessary.

Overall installation of the pipe work, pumps, macerators and other fixtures will be several thousand pounds.

Other options are to install eco-options like a composting toilet, or rainwater collecting systems.

Interiors

Like your home, your options when it comes to interior designs are essentially limitless, with prices to match.

You could install budget laminate flooring for around £15pm2, or luxurious hardwood flooring for £50pm2.

Frequently asked questions about garden rooms

Adding a garden room to your home is a big step, and people often have common questions about the process.

Do I need planning permission to build a garden room or garden office?

In most cases, you won’t need planning permission before constructing a garden room, as most are covered by permitted development rights.

Under planning rules, garden rooms are classed as outbuildings, and to be exempt from needing planning permission they must be under a certain size, depending where they are on your property:

• If it is within 2m of your boundary, it must be less than 2.5m tall.
• If it is further away, it can rise to 4m tall at its highest point, with a maximum eaves height of 2.5m.
• It cannot cover more than half of the space of your garden.
• It must be single storey, and not have any veranda, balcony or raised platform.

These rules are stricter if you are in a conversation area, Area of Outstanding National Beauty, or have a listed property.

Can I use my garden room for anything I want?

In order to avoid having to apply for planning permission, your garden room must be considered “incidental” to your main property.

If it is used residentially - which means if people sleep in it, even occasionally - it will typically not be counted as incidental. Similarly, if you are going to work in it full time, running a business from it, it may also not be considered incidental, and you may need planning permission.

Speak to the planning department of your local authority to check your circumstances. Submitting a planning application typically costs around £170.

Does my garden room need to be covered by Building Regulations?

If your garden room won’t be used for sleeping in, and is less than 15m2, then it generally won’t need to be covered by Building Regulations. If it is between 15m2 and 30m2 it may still be exempt unless it is less than 1m from your boundary, in which case it will need to be constructed from “substantially non-combustible materials”.

When installing electrics, or connecting it to mains sewage, this will need to be done in line with Building Regulations.

Is it better to have a garden room installed by the manufacturers or to hire a separate building firm?

Garden room manufacturers will typically package its sale along with the cost of its installation. The installers will be familiar with the product and well placed to ensure it is fitted properly according to the manufacturers guidelines.

However, you may wish to hire a building firm yourself to oversee its installation. This way, you can package the creation of a foundation base along with the installation. Depending on the building firm, they may also be able to cover aspects like the decoration and electricals, though you can also hire specialists for each part of the job.

Garden room cost calculator

From a cheap garden office in a small wooden summerhouse, to a garden home office that is fully kitted out with all the specs of your own home, there are options for everyone.

There are three basic price points - simple timber rooms, off-the-peg modular options, or bespoke designs - and plenty of complicating factors even within those tiers, mostly based on size and specification.

Basic additions to consider include laying the groundwork, installing utilities, and particular finishes.

We’ve laid out three scenarios below:

• A small, basic wooden summerhouse
• A medium-sized modular garden room, connected to the utilities
• A large, bespoke unit with bifold doors