Green Retreats vs Booths: 25-Year Steel or Timber?

Green Retreats vs Booths Garden Studios is one of the few genuine head-to-heads in the UK garden room market, because the two companies have solved the same problem in opposite ways. Green Retreats builds a timber-framed room with mineral wool insulation and sells the volume story: over 17,000 rooms installed, showrooms in Buckinghamshire and Twickenham. Booths builds a steel-panel shell finished in a coated plastic skin and sells longevity: a 25-year structural guarantee and a claim of no painting or staining for the life of the building.

That is not a small distinction. It changes the guarantee, the upkeep, the way the building looks in ten years, and in one specific case it changes whether your garden room needs Building Regulations approval at all. All the figures below come from each company’s own published specifications, checked in September 2026.

The headline difference: a steel shell against a timber frame

Booths states on its garden offices page that its walls are 75mm galvanised steel-clad panels, made from Corus or Tata steel and finished in a leather-effect plastic coating. Inside, walls and ceilings are white MDF and floors are commercial-grade waterproof vinyl. The whole exterior is metal.

Green Retreats builds conventionally: a timber frame with A-star fire-rated Rockwool insulation and a reflective multi-foil breather membrane called PhotonWrap, with high-density polyurethane in a double steel-backed roof. Cladding is chosen from a range, so the outside can look like cedar, composite or painted board.

The upshot is aesthetic before it is technical. A Booths building looks like a very well-made modular unit. A Green Retreats building looks like a small piece of contemporary architecture. Both are defensible. Which you prefer will probably settle the decision faster than any specification will.

Guarantees: 25 years against 12

Booths offers a 25-year structural guarantee on the building, with a shorter five years on oak steel finishes. Green Retreats gives a 12-year structural guarantee across its standard ranges, rising to 20 years on the top X1 range, and says its buildings are designed to last over 30 years.

Booths wins that comparison on paper, and it is a real advantage. Two cautions before you weigh it too heavily. First, “structural” is a narrower word than it sounds: ask both companies in writing what it covers and, more importantly, what it excludes, since glazing units, door gear, coatings and electrics are commonly outside the headline figure. Second, a guarantee is only worth the company behind it. Check both firms at Companies House and ask whether the guarantee is insurance-backed, which means it survives the company failing.

Insulation: they publish different numbers on purpose

This is where most buyers get misled, and it is not either company’s fault.

Green Retreats publishes U-values: walls 0.35, roof 0.35 and floor 0.22 W/m²K, with glazing at 1.2. A U-value is the finished thermal performance of the whole build-up, so it is directly comparable between buildings.

Booths publishes thicknesses: 90mm Actis in the walls and ceiling, 90mm Ecotherm in the floor. That tells you what went in, not what comes out. A thick layer of one material can perform worse than a thinner layer of another, and multi-foil products in particular perform very differently depending on the air gaps either side of them.

You cannot compare 90mm against 0.35 W/m²K. Ask both companies for the same figure. If a supplier will not give you a wall U-value, that is information in itself. For context, Green Retreats’ standard 0.35 wall is a long way off the roughly 0.18 expected of a new house wall, which is entirely legal because a garden room under 30m² is normally outside Building Regulations. It does mean a standard-spec room costs more to heat than the marketing suggests. Green Retreats’ X1 range quotes a wall U-value of 0.14, which is genuinely good, so the gap within one company’s own catalogue is wider than the gap between the two companies.

The boundary rule that can decide it for you

Here is the point almost nobody raises, and it can settle the choice outright.

Under Class 6 of Schedule 2 to the Building Regulations 2010, a detached single-storey building up to 30m² with no sleeping accommodation is exempt from Building Regulations if it is either more than one metre from the boundary of its curtilage, or constructed substantially of non-combustible material. Buildings under 15m² are exempt regardless.

So if your plot forces a room of between 15 and 30m² to sit within a metre of a fence, a timber-framed building takes you into a Building Regulations application while a substantially non-combustible one may not. Booths’ galvanised steel exterior is squarely aimed at that situation.

Do not treat that as an automatic pass. “Substantially of non-combustible material” is a judgement about the whole building, not the outer skin alone, and internal MDF linings and coatings are part of the picture. Put the question to your local building control team before you order, and get the answer in writing. But if your garden is tight, ask both companies about it early, because it can decide the whole thing.

Glazing, and how each one feels inside

Booths fits low-energy A-grade sealed units it describes as thermally equivalent to triple glazing, with toughened glass and enhanced sound insulation. Green Retreats quotes a glazing U-value of 1.2 W/m²K on its standard specification, and the X1 range adds acoustic laminated glass and insurance-grade locks as standard.

Note again that one company gives you a number and the other gives you a comparison. “Thermally equivalent to triple glazing” is a claim you can ask to see backed with a U-value or a window energy rating.

Inside, Booths is the more standardised product: white MDF walls and ceiling, vinyl floor, a clean finish that suits an office or a therapy room. Green Retreats offers more freedom over layout and finish, which matters more if the room is going to be a living space rather than a workspace.

Maintenance and how each ages

Booths claims zero maintenance for 25 years or more, with no painting or staining and only an occasional wipe down. For a coated steel exterior that is a credible claim rather than a marketing one.

A timber-clad Green Retreats building depends on the cladding you choose. Cedar will silver unless it is treated, painted board needs recoating on a cycle, and composite cladding sits in between. None of that is a fault, but it is a real, recurring job, and if nobody in the household is going to do it then the low-maintenance route is the honest choice.

Buying or renting

Booths offers its studios to rent monthly as well as to buy, with maintenance included. Green Retreats sells its buildings.

Renting suits a specific case: a business that wants the cost as an operating expense, a temporary need such as childcare or a two-year work-from-home arrangement, or a rented property where you cannot leave a permanent building behind. For a homeowner planning to stay put, buying almost always works out better, and a garden room is one of the few outbuildings that can add value at sale.

Which should you choose?

Choose Booths if the room must sit within a metre of a boundary, you want the longest structural guarantee available, you do not want to maintain the outside, or renting suits your circumstances better than buying.
Choose Green Retreats if appearance matters to you, you want a timber-clad building that reads as architecture rather than a unit, you want a specific layout, or you want the option of a very high insulation specification through the X1 range.
Get both to quote if you are undecided. Ask each for the wall U-value, the full written guarantee terms, the lead time and the site preparation you will have to pay for separately. Those four answers separate garden room companies far more reliably than the brochure does.

Our individual write-ups go into more detail on each: the Green Retreats review and the Booths Garden Studios review.

Frequently asked questions

Is Booths or Green Retreats better insulated?

You cannot tell from the published figures, because they are not the same kind of figure. Green Retreats publishes U-values (walls 0.35 W/m²K on the standard range, 0.14 on the X1). Booths publishes insulation thicknesses (90mm Actis in walls and ceiling). Ask both for a wall U-value and compare those.

Which company gives the longer guarantee?

Booths, on paper: 25 years structural, against 12 years from Green Retreats on standard ranges and 20 years on the X1. Ask each for the written terms, since “structural” typically excludes glazing, door gear and electrics, and check whether the cover is insurance-backed.

Does a steel garden room avoid Building Regulations?

It can. A detached single-storey building up to 30m² with no sleeping accommodation is exempt if it is over one metre from the boundary or built substantially of non-combustible material. A non-combustible building can therefore sit closer to a fence and stay exempt. Confirm it with your local building control before ordering.

Do either of them need planning permission?

Usually not. Most garden rooms are permitted development as long as they are single storey, within the height limits, used for purposes incidental to the house and not covering more than half the garden. Conservation areas, listed buildings and any sleeping use change the answer. Green Retreats says permission is rarely needed for its buildings and will handle an application where one is required.

How long does installation take?

Booths publishes one day for small studios, two to three days for larger units and five to six days for the biggest. Green Retreats does not publish a standard on-site build time, so ask when you quote. On-site time is not the same as lead time, which is measured in weeks for both.

Can you rent a garden room instead of buying one?

Booths offers monthly rental with maintenance included, which is unusual in this market. Green Retreats sells outright. Renting suits temporary needs and rented homes; if you are staying put, buying is normally the better value.

For more on how to compare any two suppliers on the same terms, start with our guide to what to look for in a garden room, or browse the rest of Best Garden Room.