How Much Does a Garden Room Cost in 2026?
The average garden room cost in the UK is £10,000 to £30,000 for a properly insulated garden room or garden office, fully installed. A garden office cost sits at the lower end if you skip plumbing; a garden room with shower and toilet costs more. The final price depends mainly on size, build quality, and whether you go for a self build garden room or a fully fitted bespoke option.
£18,000
Average cost
£5,000+
Budget option
£35,000+
Premium build
£800–£2,000
Cost per m²
Prices updated April 2026 · Based on industry data and contractor submissions.
Most garden rooms do not need planning permission under permitted development rights, provided they are single storey and under 2.5m eaves height. Electrical work must be carried out by a Part P registered electrician. Always check with your local authority before ordering.
Garden Room Prices at a Glance
Prices below cover the building itself, fully installed. Groundworks, electrical connection from the house, and internal fit-out are often extra - see the additional costs section below.
Basic shed/summerhouse (not insulated)
Timber shed or summerhouse - not suitable for year-round use
£3,500
£2,000 – £5,000
Insulated flat-pack (self-build)
DIY assembly, insulated panels, basic electrics
£8,000
£5,000 – £12,000
Mid-range bespoke office (3m × 3m)
Professionally built, fully insulated, electrics included
£14,000
£10,000 – £18,000
Premium garden office (4m × 3m)
High-spec insulation, fitted interior, full electrics and heating
£20,000
£15,000 – £25,000
Large garden room (5m × 4m+)
Spacious room for multi-purpose use or studio
£27,000
£20,000 – £35,000+
Brick garden room
Block or brick built, insulated, plastered interior finish
£30,000
£20,000 – £40,000
Luxury studio with bathroom
Premium build with WC/shower, kitchenette, and high-end finishes
£35,000
£25,000 – £45,000
Cost by Size
| Size | Total Range |
|---|---|
| 9m² (3m × 3m) | £8,000 – £18,000 |
| 12m² (4m × 3m) | £10,000 – £24,000 |
| 15m² (5m × 3m) | £12,000 – £30,000 |
| 20m² (5m × 4m) | £16,000 – £40,000 |
Per m² cost varies with specification - flat-pack sits at the lower end, bespoke builds with premium finishes at the upper end.
Additional Costs to Budget For
The headline price of a garden room rarely includes everything. These are the costs that catch people out - budget for them from the start.
| Item | Typical Cost |
|---|---|
| Groundworks and base (concrete slab or screw piles) | £1,000 – £3,000 |
| Electrical connection from house | £500 – £1,500 |
| Plumbing (WC or kitchenette) | £1,500 – £3,500 |
| Heating (electric panel heaters) | £200 – £500 |
| Internet/ethernet connection | £100 – £300 |
| Landscaping around the building | £500 – £2,000 |
| Internal fit-out (desk, shelving, storage) | £300 – £1,500 |
| Blinds or curtains | £100 – £400 |
Total additional costs typically add £2,500 to £6,000 on top of the building price, depending on what you need.
What Affects the Cost of a Garden Room?
Size
The most obvious factor. Every additional square metre adds £800 to £2,000 to the total cost. A 9 square metre garden office (3m x 3m) is enough for a single workstation and small meeting area. A 20 square metre room (5m x 4m) gives you a genuinely spacious multi-purpose space. Decide what you actually need the room for before committing to a size.
Insulation quality
Cheap garden rooms use thin insulation (25mm or less) that is not adequate for year-round use. A properly insulated garden office uses 50mm to 100mm of rigid PIR or phenolic insulation in the walls and 100mm or more in the roof. Better insulation costs more upfront but saves on heating bills and makes the room genuinely comfortable in all seasons.
Flat-pack vs bespoke
A flat-pack garden room you assemble yourself starts from £5,000 to £8,000 for a basic insulated model. A bespoke garden office, designed to your specification and professionally built on site, typically costs £12,000 to £30,000. The bespoke option gives you more control over the design, better build quality, and a proper warranty.
Foundations and access
If your garden is flat, accessible, and close to the house, groundworks are straightforward and cost around £1,000 to £2,000. Sloping ground, poor access (narrow side passages, no rear vehicle access), or a long distance from the house all add cost. Screw-pile foundations work well on difficult ground and avoid the mess of pouring concrete.
Plumbing
A garden office without plumbing is significantly cheaper and simpler. Adding a WC costs £1,500 to £2,500, a full shower room £2,500 to £3,500, and a kitchenette £1,500 to £2,500. Plumbing also triggers Building Regulations requirements for drainage (Part H), which adds paperwork and inspection costs.
Your location
Labour rates and installation costs vary by region. London and the South East are typically 15 to 25% more expensive than the national average. The North and Wales tend to be 10 to 15% below average. The building itself costs roughly the same wherever you are - it is the groundworks, installation labour, and electrical connection that vary.
Garden Room vs Extension vs Loft Conversion
If you need extra space, a garden room is not your only option. Here is how the three most common approaches compare for a similar amount of floor area.
| Factor | Garden Room | Extension | Loft Conversion |
|---|---|---|---|
| Typical cost | £10,000 – £30,000 | £25,000 – £50,000 | £25,000 – £55,000 |
| Duration | 2–4 weeks | 8–16 weeks | 4–8 weeks |
| Planning permission | Usually not needed | Often required | Usually PD |
| Building Regs | Electrics only (Part P) | Full approval | Full approval |
| Disruption | Minimal | High | Moderate |
| Value added | Moderate | High (10–20%) | High (10–20%) |
| Attached to house? | No - separate building | Yes | Yes |
Want to compare extension or loft conversion costs in more detail? Extension cost guide · Loft conversion cost guide
Popular UK Garden Room Brands
There are dozens of garden room companies in the UK, ranging from local joiners to national brands with showrooms. These are some of the most established names - but always get quotes from local suppliers too, as they can often match the quality at a better price.
Green Retreats
Large national supplier. Showrooms in Buckinghamshire and Yorkshire. Mid to premium range. Known for quick installation.
Cabin Master
Nottingham-based. Large showroom. Mid-range to premium. Strong online reviews.
Booths Garden Studios
Norfolk-based, nationwide delivery. Highly regarded build quality. Premium end of the market.
Smart Garden Offices
Mid-range supplier with a good reputation. Various standard sizes with customisation options.
Arka Living
Contemporary designs, flat-pack and installed options. Competitive pricing for the specification.
Brand mentions are for reference only - we are not affiliated with any garden room supplier. Always get multiple quotes and visit a showroom or completed installation before committing.
Garden Room Costs by Region
Average fully installed price for a mid-range insulated garden office (approximately 12m², including base, electrics, and heating) by UK region.
| Region | Average Cost | vs National |
|---|---|---|
| London | £22,000 | +25% |
| South East | £20,000 | +14% |
| East of England | £19,000 | +8% |
| South West | £18,000 | +3% |
| Midlands | £17,500 | Average |
| Yorkshire | £16,000 | -9% |
| North West | £16,500 | -6% |
| North East | £15,000 | -14% |
| Scotland | £16,000 | -9% |
| Wales | £15,500 | -11% |
Based on industry data for a mid-range insulated garden office, fully installed including groundworks and electrical connection.
How to Get Your Garden Room for Less
A garden room is already cheaper and less disruptive than an extension, but there are ways to bring the cost down further without sacrificing the things that actually matter.
Consider a flat-pack or self-build option
If you are reasonably handy, a flat-pack garden room can save you £3,000 to £8,000 compared to a fully installed bespoke model. Several UK suppliers sell insulated panel kits designed for DIY assembly - you still need an electrician for the electrics, but the structure itself is manageable with a friend and a weekend. Check the insulation specification carefully before buying.
Order in winter or early spring
Garden room companies are busiest from April to September. Order in November to February and you will often get a better price, shorter lead times, and sometimes a discount on groundworks. The build itself is fine in cold weather - the insulation and structure do not care about the temperature.
Skip the plumbing
Adding a WC, shower, or kitchenette to a garden room pushes the cost up by £1,500 to £3,500 and triggers Building Regulations requirements for the drainage. If your garden room is a home office, you genuinely do not need plumbing - you are thirty seconds from the house. Save the money and spend it on better insulation instead.
Prepare the base yourself
If you have a reasonably flat, accessible garden, laying a concrete slab or preparing a gravel pad for screw piles is within reach for a competent DIYer. Groundworks typically cost £1,000 to £3,000 when done professionally. Doing it yourself could save £500 to £1,500, though you need to get the levels right - a wonky base means a wonky building.
Get three quotes and compare the detail
Garden room quotes are notorious for varying wildly in what is included. One supplier might quote £15,000 all-in including base, electrics, and heating. Another might quote £12,000 for the building only, with groundworks, electrical connection, and heating all extra. By the time you add those up, the cheaper quote is actually more expensive. Always ask for a full written breakdown.
Choose the right size - not the biggest
It is tempting to go large, but every extra square metre costs £800 to £2,000. A 9 square metre (3m x 3m) garden office is genuinely plenty for a single desk, bookshelves, and a comfortable chair. Going to 12 square metres adds £2,000 to £6,000. Only size up if you actually need the extra space for equipment, a meeting area, or shared use.
What to Expect: The Garden Room Installation Process
From first enquiry to sitting at your desk, here is what typically happens.
- 1
Research and quotes
Get at least three quotes from different suppliers. Visit showrooms if possible. Check what is included - groundworks, electrics, and heating are commonly excluded from headline prices. Confirm your garden room qualifies under permitted development (most do).
- 2
Site survey and base preparation
Your chosen supplier will survey the site to check levels, access, and the best position for the building. The base is then prepared - either a concrete slab (allow 3 to 7 days for pouring and curing) or screw piles (1 to 2 days). Some suppliers include this in their price, others do not.
- 3
Build or install the structure
The frame, insulation, cladding, roof, windows, and doors go up. A flat-pack takes 2 to 5 days. A bespoke build takes 1 to 3 weeks. Pre-fabricated modular rooms can be craned into position in a single day if access allows.
- 4
Electrical connection and internals
A Part P registered electrician runs a dedicated supply from your house consumer unit to the garden room. Internal electrics - sockets, lighting, consumer unit, and heating - are installed and tested. The electrician issues an Electrical Installation Certificate.
- 5
Fit-out and finishing
Internal decoration, flooring, furniture, and any bespoke storage or shelving are completed. Internet connectivity is set up - either via ethernet run through the same duct as the electrical cable, or a mesh Wi-Fi extender. Landscaping around the building finishes the job.
Frequently Asked Questions
How much does a garden room cost in the UK?
A typical insulated garden room in the UK costs between £10,000 and £30,000 fully installed. A basic flat-pack or self-build model starts from around £5,000. A mid-range bespoke garden office (3m x 3m) runs £10,000 to £18,000. A premium fully fitted garden office (4m x 3m) costs £15,000 to £25,000. Larger garden rooms with bathrooms can reach £45,000.
Do I need planning permission for a garden room?
Most garden rooms do not need planning permission under permitted development rights, provided the building is single storey with a maximum eaves height of 2.5 metres, does not exceed 3 metres in overall height (or 4 metres with a dual-pitched roof), covers no more than 50% of the garden area, and is not forward of the principal elevation. Properties in conservation areas, listed buildings, and those with removed PD rights will need a planning application. Always check with your local authority first.
How much does it cost to run electricity to a garden room?
Running a dedicated electrical supply from your house to a garden room typically costs £500 to £1,500, depending on the distance from the consumer unit and the complexity of the installation. The cable is usually run underground in protective ducting. All work must be carried out by a Part P registered electrician who will issue an Electrical Installation Certificate. Do not attempt to DIY the electrical connection from the house - it is notifiable work under Building Regulations.
Is a garden room cheaper than an extension?
Yes, significantly. A garden room extension alternative typically costs £10,000 to £24,000 for 12 square metres, while a single-storey rear extension of the same floor area would cost £25,000 to £50,000 or more. The garden room is also quicker to install (2 to 4 weeks vs 8 to 16 weeks), causes far less disruption, and usually does not need planning permission. A brick built garden room costs more (£20,000 to £40,000) but still undercuts a traditional extension. The main trade-off is that a garden room is a separate building - you have to walk outside to get to it.
How long does a garden room take to build?
A flat-pack garden room takes a weekend to a week if you are doing it yourself, or 2 to 5 days for a professional installation. A bespoke garden office typically takes 2 to 4 weeks from groundworks to handover. Pre-built modular garden rooms can be craned into place in a single day, though you still need the concrete base or screw piles prepared in advance, which adds a few days.
What is the cheapest way to get a garden room?
The cheapest route is a flat-pack garden room that you assemble yourself, starting from around £5,000 to £8,000 for a basic insulated model. If you are handy, you can also build one from scratch using a timber frame, SIP panels, or stud walls with rigid insulation. Ordering in winter or early spring often gets you a better deal, as most garden room companies are quieter outside the peak season of April to September.
Do garden rooms need Building Regulations?
Garden rooms used as offices, gyms, or studios are generally exempt from Building Regulations if the floor area is under 30 square metres and they are not used for sleeping. However, the electrical installation must comply with Part P - use a registered electrician. If you add plumbing (a WC or shower), the drainage must comply with Part H. If the garden room will be used as sleeping accommodation, full Building Regulations apply.
What are the best garden room brands in the UK?
Well-regarded UK garden room suppliers include Green Retreats, Cabin Master, Booths Garden Studios, Smart Garden Offices, and Arka Living. Prices and specifications vary considerably between suppliers. Visit a showroom or completed installation before committing - build quality is more important than brand name. Always ask for U-values (insulation performance), check what is included in the quoted price, and confirm whether groundworks and electrics are extra.
Written by Sarah Mitchell, Less.co.uk home improvement specialist
Last updated: · Pricing based on industry data and verified contractor submissions · Methodology
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