Green Retreats Review: 12-Year Cover, 60% Upfront

Anyone researching a Green Retreats review is usually at the same point in the process: the showroom visit went well, the quote is bigger than expected, and the company is asking for most of the money before the building exists. This is an independent look at what the company publishes about itself, what its own numbers mean, and where the contract deserves attention. We have no commercial relationship with Green Retreats and have not been supplied with a building.

Every figure below comes either from the company’s own website in September 2026 or from the public record, and is attributed so you can check it.

Who the company actually is

Green Retreats is one of the largest garden room makers in the UK. Its own About page gives the founding date as 2005, claims 17,000 garden buildings installed since, and describes a 60,000 square foot factory at Westcott Venture Park near Aylesbury, opened in 2022. There are two showrooms: the Buckinghamshire flagship with 21 buildings on display, and Twickenham with four.

On the public record, GREEN RETREATS LIMITED is company number 08305447, incorporated in November 2012, active, registered at the Westcott address under SIC code 43999. It files accounts as a medium sized company, most recently for the year to 31 March 2025, with no gaps in its filing history and no insolvency record.

That matters more here than it would with most purchases, for a reason covered further down: you pay for a Green Retreats building substantially in advance.

The ranges, and where the money goes

The line-up runs from a budget range to what is effectively a small house. Starting prices published on the company’s own range pages in September 2026 give the shape of it, though these change and should be checked before you plan around them:

B-Range: the entry point, from around £9,500.
G-Range: the core range, from roughly £23,800, offered in over 70 size configurations.
A-Range: apex roof buildings, from about £31,000.
X1: the flagship, from roughly £50,000.
The Annex: buildings for full time living, including building regulations approval, from about £63,000.

The gap between the B-Range and the G-Range is where most buyers end up making a decision they did not expect to make. Specification, glazing, cladding and included groundworks all differ by range, so comparison with another supplier has to be done range by range, not brand against brand.

What the fabric specification actually means

Green Retreats publishes U-values, which is more than many competitors do, and they are respectable numbers for a garden building: glazing 1.2, walls 0.31 to 0.35 depending on range, roof 0.24 to 0.35, and floor 0.22, all in watts per square metre kelvin, with high density polyurethane insulation.

Set those against the standards England applies to habitable space and the picture is clear. Table 4.2 of Approved Document L, which governs new elements in existing dwellings, requires a wall at 0.18, a roof at 0.15, a floor at 0.18 and a window at 1.4. The glazing beats the habitable standard comfortably. The opaque fabric does not come close to it.

That is a description of what a garden room is rather than a criticism. Outbuildings are not built to dwelling standards, which is why they go up under permitted development without building regulations approval. The practical effect is running cost: the walls and roof lose heat roughly twice as fast per square metre as a compliant extension, so budget for heating. The Annex is the range that carries building regulations approval, and the price step reflects it.

The guarantee: 12 years, structural

The company’s own FAQ is unambiguous: “All Green Retreats garden rooms come with a 12-year structural guarantee.” It also states the buildings are designed to last over 30 years with maintenance. You will see a 20 year figure quoted in places online for the X1; the company’s own guarantee page gives 12 years across the ranges, so get whatever applies to your building written into your order.

Read the word structural carefully. It is not the same as cover on doors, ironmongery, glazing units, heating or electrics, which carry separate and much shorter manufacturer warranties. The commonest complaint in public reviews of garden rooms generally, this company included, is doors needing adjustment after a few years, a moving parts issue rather than a structural one. Ask what the door and glazing warranty period is.

Foundations, lead time and site access

Standard buildings include professionally fitted ground screw foundations in a grid, with depth assessed on installation day. The B-Range treats this as an option rather than an inclusion, which is another reason the entry price is not a like for like comparison with the ranges above it.

A black timber clad garden room with a sedum roof and open doors — A timber clad garden room with a sedum roof, built by OKOPOD. Shown for illustration: this is not a Green Retreats building. | An OKOPOD with Yakisugi cladding and a sedum roof by Lorna Satchell (CC BY 4.0), via Wikimedia Commons, https://commons.wikimedia.org/wiki/File:An_OKOPOD_with_Yakisugi_cladding_and_a_sedum_roof.jpg

The company asks for the ground to be cleared and level to within 200mm before installation. That tolerance is the single most common source of unexpected cost on garden room projects: a sloping or overgrown plot needs groundworks that are not in the quote. Walk your site with a spirit level and a tape before you sign anything.

Base work is quoted at half a day to a full day, the building at two to five days on site, and the overall build at one to 15 days depending on design. Electrical connection from the house is available at extra cost with a Part P certificate, or you can use your own electrician. Ground screws need machine access, so a narrow side return changes the job significantly.

Planning permission and the annexe question

Most garden rooms are built under permitted development as an outbuilding incidental to the house, which is why no planning application is normally needed. Flats and listed buildings are outside that, and Article 4 directions can remove the right in conservation areas. Green Retreats says it manages the application where one is needed and quotes a 92% success rate, a figure that is its own and not independently verifiable. CAD drawings are quoted at £200 each with roughly a week’s lead time.

The important line is what a garden room is not. The company states plainly that its garden rooms are “not designed to be lived in as they do not comply to building regulations”, and points anyone wanting living accommodation at The Annex range instead. That is the honest answer, and it is worth hearing before a salesperson elsewhere tells you otherwise. If you want somewhere a relative can sleep permanently, you are buying a different, more expensive and more regulated product. See our guides to garden room planning permission and garden room annexes for the detail.

The payment schedule is the thing to look at hardest

Per the company’s published terms, the sequence is a £300 holding deposit to secure an installation slot, 60% of the balance six weeks before installation to start production, 30% on the final day of construction, and the last 10% on project completion.

So roughly 90% of the money is with the supplier by the time the building is finished, and 60% of it before manufacturing even begins. This is standard practice across the bespoke garden building trade rather than anything unusual to this company, and it is the reason the Companies House check above is worth doing on any supplier you are considering. Two practical protections: pay the deposit and as much of the balance as possible by credit card, which brings Section 75 protection on transactions over £100, and ask in writing what happens to your money if the company cannot deliver.

What the reviews say, and what they do not

On Trustpilot the company holds a 4.9 out of 5 score from 1,257 reviews, with 91% at five stars. That is a genuinely strong record for a business selling a five figure product, and the recurring themes are the showroom experience, build quality and installation teams.

The number worth noticing is the 3% at one star, a larger share than the two and three star reviews combined. That polarised shape is normal for construction: most projects run smoothly and a small number go wrong badly. Read the one star reviews and the company’s replies rather than the average, and pay attention to whether complaints concern the product or the aftercare, because those tell you different things.

Verdict: who should buy

Green Retreats suits a buyer who wants a manufactured, installed, guaranteed building with a single point of responsibility, and who values walking through 21 buildings before committing. The published U-values, the 12 year structural guarantee, in-house installation and clean filed accounts add up to a lower risk purchase than much of this market offers.

It suits you less if you are price led. The B-Range entry point exists, but the specification that most buyers actually want sits in the G-Range and above, and at that level a good local builder or a smaller regional specialist may build something better insulated for similar money. It also suits you less if you want somewhere to sleep, since that is a different product with building regulations attached.

Either way, do the same three things: check the supplier at Companies House, walk the site for access and level, and get the payment schedule and warranty terms in writing before the deposit leaves your account. Our comparison of UK garden room companies covers the alternatives.

Frequently asked questions

Is Green Retreats a reputable company?

On the public evidence, yes. GREEN RETREATS LIMITED is active at Companies House, files medium company accounts on time, has no insolvency history, and holds a 4.9 out of 5 Trustpilot score from more than 1,200 reviews. That is not a guarantee of a smooth project, but it is a materially better starting position than an unfilable trading name with a handful of reviews.

How much does a Green Retreats garden room cost?

Its published starting prices in September 2026 ranged from roughly £9,500 for the entry B-Range to about £63,000 for The Annex, with the mainstream G-Range starting near £23,800. Starting prices are for the smallest size in each range with base specification, so the quoted figure for the building most people actually choose will be higher.

Do I need planning permission for one?

Usually not. Garden rooms normally fall under permitted development rights as outbuildings incidental to the house, subject to height, siting and coverage limits. Flats, listed buildings and areas with an Article 4 direction are the common exceptions. Check with your council before ordering.

Can you sleep in a Green Retreats garden room?

Not in the standard garden room ranges. The company states its garden rooms are not designed to be lived in because they do not comply with building regulations. Its Annex range is the product intended for full time living and includes building regulations approval.

What does the 12 year guarantee actually cover?

It is described as a structural guarantee, covering the structure of the building rather than the components fitted into it. Doors, glazing units, heating and electrical items generally carry their own shorter manufacturer warranties. Ask for those periods in writing alongside the headline figure.