July 28^th, 2025

As demand for home-based workspaces and creative studios continues to rise, garden offices have become a staple of modern residential projects.

 

While some clients opt for modular or temporary structures, long-term value lies in a properly constructed building, one that won’t rattle or shake in every gale, is well insulated for year-round comfort, keeps pests out, and won’t suffer from damp or leaks.

 

But how much does it cost to build an office in a garden? In this guide, we’ll break down the installation costs so you can weigh up the options, including with and without a WC and kitchenette that includes:

 

• Sink with mixer tap
• Base unit with a small worktop
• Under-counter fridge
• Microwave
• Basic storage for cups, cutlery, and dry goods

 

We also provide a basic example with a felt roof system and engineered wood floor—two straightforward swaps that can help reduce the overall project cost and make the build more budget-friendly.

 

 

Garden Office Cost Calculations

The costs in this guide are based on a garden office comprising 12m². We’ve also included a cost per square metre, so you can easily work out the costs for similar projects.

In terms of build specification, BuildPartner gives you three broad options to choose from:

 

• Basic spec is a basic finish; e.g., Leyland, Everest, Wickes.
• Standard spec is a standard finish; e.g., Dulux, Hamilton, Slim Line.
• Premium spec is a high-spec finish; e.g., Farrow & Ball, Fine Line, Siemens.

 

In this article, we’ve provided a breakdown of the cost of building a garden office to a standard specification. In addition, we have provided three different benchmarks to show the range of pricing you can expect among different contractors. These are:

 

• Low benchmark – smaller companies are generally lower cost but less specialised and with low project management function; good for low/mid-spec projects and tight budgets.
• Mid benchmark – medium-sized companies offer a balanced mix of cost-effectiveness and specialisation; good for mid-range projects for effective execution within moderate budgets.
• High benchmark – larger companies generally have a higher cost base but can handle a wide variety of specialist tasks; good for mid/high-spec projects and project management.

 

The specification and benchmark you choose will have a major impact on the overall cost, so it’s important to align them with your budget and the level of finish you’re aiming for.

 

Cost Of Building A Garden Office With Kitchenette & WC

The table below shows the average cost of building a garden office that includes a kitchenette and a separate WC:

 

Garden Office – With Kitchenette & WC	Total Average Build Cost			Average Cost Per Sq Metre
	Low Benchmark	Mid Benchmark	High Benchmark	Low Benchmark	Mid Benchmark	High Benchmark
East Anglia	£40,821	£45,645	£50,098	£3,402	£3,804	£4,175
Greater London	£43,573	£50,168	£54,601	£3,631	£4,181	£4,550
Inner London	£44,420	£50,018	£51,977	£3,702	£4,168	£4,331
Midlands	£39,605	£44,285	£48,606	£3,300	£3,690	£4,050
North England	£38,615	£43,179	£47,391	£3,218	£3,598	£3,949
Northern Ireland	£39,723	£43,138	£48,530	£3,295	£3,595	£4,044
Scotland	£39,902	£44,618	£48,970	£3,325	£3,718	£4,081
South East	£39,592	£43,983	£49,119	£3,586	£3,984	£4,401
South West	£39,970	£46,104	£50,606	£3,436	£3,842	£4,217
Wales	£38,705	£43,280	£46,536	£3,225	£3,607	£3,878
Average	£40,493	£45,442	£49,643	£3,412	£3,819	£4,168

All costs exclude VAT.        

 

Here’s what the data shows for building a garden office that includes a kitchenette and a separate WC:

 

• It costs 8% more to build in Inner London.
• The minimum cost is £38,615, and the maximum cost is £54,601.
• The total average cost is £45,193, or £3,800 per square metre.

 

Start your free trial with BuildPartner to get a bespoke estimate of your construction project within minutes.

Cost Of Building A Garden Office Without Kitchenette & WC

The table below shows the average cost of building a garden office without a kitchenette and a separate WC (as per the example above):

 

Garden Office – No Kitchenette or WC	Total Average Build Cost			Average Cost Per Sq Metre
	Low Benchmark	Mid Benchmark	High Benchmark	Low Benchmark	Mid Benchmark	High Benchmark
East Anglia	£28,940	£32,360	£35,518	£2,412	£2,697	£2,960
Greater London	£30,789	£35,507	£38,523	£2,566	£2,959	£3,210
Inner London	£31,376	£35,379	£36,667	£2,615	£2,948	£3,056
Midlands	£28,099	£31,420	£34,486	£2,342	£2,618	£2,874
North England	£27,257	£30,479	£33,452	£2,271	£2,540	£2,788
Northern Ireland	£28,138	£30,690	£34,526	£2,344	£2,558	£2,877
Scotland	£28,144	£31,471	£34,541	£2,345	£2,623	£2,878
South East	£27,986	£31,097	£34,347	£2,535	£2,817	£3,111
South West	£28,293	£32,705	£35,899	£2,438	£2,725	£2,992
Wales	£27,336	£30,566	£32,848	£2,278	£2,547	£2,737
Average	£28,636	£32,167	£35,081	£2,415	£2,703	£2,948

 All costs exclude VAT.

 

Here’s what the data shows for the cost of building a garden office without a kitchenette and a separate WC:

 

• The minimum cost is £27,251, and the maximum cost is £38,523.
• The total average cost is £31,961, or £2,689 per square metre.

 

Cost Of Building A Garden Office Using Felt Roof & Laminate Floor

The table below shows the average cost of building a garden office (without WC and kitchenette) using a felt roof system instead of roof tiles, and laminate flooring in place of engineered oak—two straightforward swaps that can help reduce the overall project cost and make the build more budget-friendly.

 

Garden Office – With Felt Roof System & Laminate Floor	Total Average Build Cost			Average Cost Per Sq Metre
	Low Benchmark	Mid Benchmark	High Benchmark	Low Benchmark	Mid Benchmark	High Benchmark
East Anglia	£25,962	£29,030	£31,862	£2,163	£2,419	£2,655
Greater London	£27,608	£31,758	£34,429	£2,301	£2,647	£2,869
Inner London	£28,069	£31,719	£32,818	£2,339	£2,643	£2,735
Midlands	£25,178	£28,154	£30,901	£2,098	£2,346	£2,575
North England	£24,415	£27,300	£29,964	£2,035	£2,275	£2,497
Northern Ireland	£23,927	£26,754	£29,364	£1,994	£2,230	£2,447
Scotland	£25,146	£28,118	£30,861	£2,095	£2,343	£2,572
South East	£25,062	£27,876	£31,092	£2,088	£2,323	£2,591
South West	£25,374	£29,339	£32,205	£2,114	£2,445	£2,684
Wales	£24,507	£27,403	£29,449	£2,042	£2,284	£2,454
Average	£25,525	£28,745	£31,294	£2,127	£2,395	£2,608

 All costs exclude VAT.

 

Here’s what the data shows for the cost of building a garden office with a felt roof system (instead of tiles) and using laminate flooring (instead of engineered oak):

 

• The minimum cost is £23,927, and the maximum cost is £34,429.
• The total average cost is £28,521, or £2,377 per square metre.

 

Average Cost Of Building A Garden Office

So, how much does it cost to build a garden office in the UK? Based on the three types of installations covered in this article, it costs on average (when using a mid-benchmark contractor):

• Garden Office – With Kitchenette & WC: £45,442, or £3,819 per square metre.
• Garden Office – No Kitchenette or WC: £32,167, or £2,703 per square metre.
• Garden Office – Felt Roof System & Laminate Floor: £28,745, or £2,395 per square metre.

These figures show just how much the total cost can vary depending on the type and scope of your project. Key factors include whether you include a kitchenette or WC, and whether you opt for more affordable finishes like flooring and roofing.

It’s also worth noting that these projects were based on a standard specification, so your final cost could be lower or higher depending on the quality of materials you choose.

Start your free trial with BuildPartner to get a bespoke estimate of your construction project within minutes. Please remember that all costs exclude VAT.

 

Frequently Asked Questions About Building A Garden Office

Here are some answers to frequently asked questions about building a garden office.

Are garden offices cheaper than house extensions or loft conversions?

Garden offices are generally cheaper because they avoid the expensive structural work required for house extensions and loft conversions.

Quite often, their foundations aren’t connected to the main house, so there’s no need to knock through walls or install steel beams and supporting walls, which saves on labour, materials, and the cost of making good plasterwork, painting, flooring, and decoration.

Plumbing is often unnecessary for a garden office, and you’ll likely avoid the time and cost of full planning applications.

Do I need planning permission to build a garden office?

In most cases, garden offices can usually be built under Permitted Development Rights, meaning you don’t need formal planning permission. However, it must be a single storey, take up less than 50% of your garden, and not be used as a separate living space. A height limit of 2.5m applies (if it’s within 2 metres of a boundary).

If your property is listed, in a conservation area, or you plan to run a business with regular visitors, you may need permission. It’s always best to double-check with your local planning authority.

Is it possible to make a garden office completely off-grid?

To make a garden office completely off-grid, you’ll need solar panels with battery storage for power, and a rainwater harvesting and filtration system for potable water (for making hot drinks and washing up).

The biggest challenge is the toilet. Without drainage or plumbing, your only real option is a composting toilet… not exactly everyone’s preferred choice.

Composting toilets use a carbon additive like sawdust to break down waste, but disposal is a bit of a chore. It’s far more convenient to simply pop inside to use the nearest bathroom. As for the internet, your existing Wi-Fi with a signal booster should keep you reliably connected.

What if there is limited access to the garden for construction equipment?

This is a common issue for Victorian terraces and even some newbuilds where the garden is only accessible through the house or a narrow side passage. In most cases, it’s still possible to build a garden office, it just requires a bit more planning.

Many contractors will carry materials through the house and use protective floor coverings to avoid damage. However, limited access can increase labour time and delivery costs slightly, so it’s worth flagging this early during quotes and site surveys.

If carrying out the work during rain, expect mess to be tracked through the house, so additional cleaning and protective measures may be needed to keep the property tidy. It’s also a good idea to factor in the cost of a professional upon completion.

Does a garden office change a property’s council tax band?

A garden room or office usually doesn’t affect the property’s council tax band because it’s considered an outbuilding, not part of your main living space. Council tax bands are based on the internal floor area of the primary residence, so standalone garden offices are typically excluded.