SteelRoot Wide 4.00 Galvanised-Steel Greenhouse Brochure

The fourth option.

Serious British growers have had three structures to choose from, and none of them quite fit.

A polycarbonate aluminium box from the garden centre that twists in the first proper storm. A polytunnel whose film is a consumable, perishing at the hoops every few seasons and ending up in landfill. Or a heritage glasshouse priced at £8,000 and up, which puts the conversation out of reach for most growers.

SteelRoot is the fourth. A modular galvanised-steel arch greenhouse, built for the British weather you actually get, sold at the price a serious grower can reach. It gives you from 16 m² up to 48 m² of year-round growing space on a closed-section steel frame with no organic material to rot, extendable in 2 m steps as your growing ambition develops.

We do not claim absolute storm survival, because no greenhouse can stand behind that. We tell you how it is built instead, and let the construction answer the question.

• Modular galvanised-steel arch, built once and grown into for a decade.
• Engineered for Yorkshire wind, not a Continental display garden.
• Manufactured by a workshop with over 20 years of greenhouse-making expertise.
• Manufactured in Poland, UK-stocked, UK-backed.
• One of three Waldenhaus lines, alongside the NORDIC timber range and OBLO / CUBIO saunas.

Structure, not adjectives.

Wind performance is not about mass. It is about structure plus correct anchoring, and SteelRoot answers with four working mechanisms, not an adjective.

• Closed 40 × 20 mm RHS galvanised steel, resisting twist as well as bend.
• 1.0 m standard/base arch spacing, with 0.67 m close-arch spacing available for exposed plots.
• Screw-fixed glazing with stainless screws and EPDM washers, with no spring clips to pop out.
• Ground anchors included, scaled to length, with no concrete and no setting time.
• ZAM coating (zinc-aluminium-magnesium) on the steel frame.

The spec, in plain sight.

We put the specification on the page, not in a PDF you only open after a problem. This is the SteelRoot Wide 4.00 m line as it ships.

• Frame: closed 40 × 20 mm rectangular hollow-section galvanised steel, ZAM coating (zinc-aluminium-magnesium), pre-drilled and bolt-assembled, with no welding or cutting on site.
• Arch spacing: 1.0 m standard/base, with 0.67 m close-arch spacing available for exposed plots.
• Glazing: 4 mm standard/base twin-wall cellular polycarbonate, with a 6 mm option, UV-stabilised top layer, covering roof, walls and gables.
• Glazing fixing: screw-fixed to the frame with stainless screws and EPDM washers, with no spring clips.
• Anchoring: ground anchors included as standard, scaled to the greenhouse length.
• Ventilation: automatic roof vents fitted as standard (wax-cylinder openers, factory-calibrated to open at around 18°C), plus opening windows in both gable doors for cross-flow.
• Doors: two-part stable doors front and rear, with upper and lower sections that open independently, each upper section held back on a cabin hook.
• Ridge: 2.30 m, convex profile for maximised internal volume.
• Assembly: self-assembly, pre-drilled and bolt-assembled, typically one day (4 m) to three days (12 m), with a cordless drill, spanner set, spirit level and step-ladder.

Five lengths, one system.

Five lengths, all 4.00 m wide and 2.30 m to the ridge. Start where your plot is today, then extend in 2 m steps later as your growing ambition outgrows the footprint.

• All prices include UK mainland delivery included.
• Self-assembly can build it: pre-drilled, bolt-assembled, no specialist tools.
• Extendable in 2 m steps later, with the same arch geometry, the same twin-wall polycarbonate options and the same anchoring system.
• 0% APR over 12 months via V12 Retail Finance available at checkout.

All five lengths share the same 4.00 m width and the same 2.30 m ridge. Only the length changes, and the room to grow. If you are between two lengths, most growers later wish they had gone longer.

Room to grow, properly.

Inside the 4.00 m width: two full growing rows, a central path you can push a barrow along, and 2.30 m of headroom at the ridge. Because the polycarbonate is permanent, there is no film to replace and no cover to lose in a storm.

Two rows, a barrow-width path

The permanent growing space, this season.

• Two growing rows plus a central working path.
• 2.30 m headroom at the ridge, so you stand and work upright.
• Optional 6 mm twin-wall polycarbonate is thicker than 4 mm hobby-grade panels, for steadier heat retention.
• No film, no replacement cycle, no annual cover cost.

Free to your kerb.

UK mainland delivery included is included in the price, typically one to two weeks from order.

A secure pallet, delivered kerbside, with a bolt-together self-assembly build and a video in the pack.

• UK mainland delivery included, typically 1 to 2 weeks.
• Kerbside pallet delivery, so check your access.
• Highlands, Outer Hebrides and Northern Isles: contact us for a delivery quote before ordering.
• Self-assembly, pre-drilled and bolt-assembled, roughly 1 day (4 m) to 3 days (12 m).
• Damage or missing parts: photograph within 48 hours and email us, and we ship replacement parts at no charge.

The ones we hear most.

1. Will it survive a real Yorkshire or coastal winter?

   The galvanised steel arch, 1.0 m standard/base arch spacing, optional 0.67 m close-arch spacing, screw-fixed twin-wall polycarbonate and included ground anchors are engineered for British storm conditions when correctly anchored. For exceptional sites such as the Outer Hebrides, the NW Scotland coast, Pennine summits or Shetland, please contact us before ordering. We do not claim absolute storm survival, because no greenhouse can stand behind that.

2. Do I need planning permission?

   Usually not, since the 2.30 m ridge sits comfortably under the 2.5 m boundary cap that defines Permitted Development for most UK domestic plots. Check with your council if you are in a conservation area, in a listed building, siting closer than 2 m to a boundary, or your outbuildings exceed 50% of the garden. A plain-language checklist is in your order pack.

3. How long does assembly take?

   Self-assembly, pre-drilled and bolt-assembled, take roughly 1 day (4 m), 2 days (6 to 8 m), or 3 days (10 to 12 m). You will need a cordless drill, spanner set, spirit level and step-ladder, with no concrete for typical UK soil. A build-along video is in your order pack.

4. How is it different from a polytunnel?

   It gives you polytunnel practicality with greenhouse permanence, and no film to replace. SteelRoot uses screw-fixed twin-wall polycarbonate on a closed steel arch, with 4 mm standard/base glazing and a 6 mm option, where a polytunnel uses tensioned polythene film that is replaced every few years and can lift in a named storm. SteelRoot is one capital outlay, where the polytunnel is lower upfront plus a recurring cover cycle.

5. What is the difference between SteelRoot and NORDIC?

   The jobs are different. NORDIC is a timber-framed greenhouse with 4 mm standard / 6 mm option polycarbonate and a warm, paintable, formal-garden look. SteelRoot is a galvanised-steel arch with 4 mm standard/base glazing and a 6 mm option, built utility-first for serious growing. Both are Waldenhaus, and we will point you to whichever fits your garden.