Products · 06

Greenhouse doors and entrances

Insulated aluminium sliding, personnel and shutter doors

A door is the largest deliberate hole in an otherwise sealed envelope, and in a greenhouse it is the point where three separate problems meet: heat, insects and traffic. Every opening leaks conditioned air, admits pests past the screening that protects the vents, and has to pass a trolley or a pallet without becoming the bottleneck of the whole operation.

The doors are aluminium, insulated, and supplied complete with their rollers, rails and handles as part of the structure rather than bought in afterwards to fit a hole that has already been built.

Interior of a completed Venlo greenhouse before planting, looking down the length of the concrete floor between column rows

The three types

The main opening is an insulated aluminium sliding door, 3,000 × 3,000 mm. Sliding rather than swinging, because a three-metre leaf on hinges is a sail: wind pressure across an open gable will take a swing door out of a person's hands, and a slider stays in its track under the same load. It also costs no floor area to operate, which matters where the crop starts a metre from the wall.

Personnel access is an insulated aluminium door 1,200 × 2,400 mm — the everyday route, sized for people rather than machines so that the large door stays closed.

At the loading and storage area there is an aluminium shutter door, sized to the vehicle and pallet movements that actually happen there.

Three-dimensional model of one Venlo bay set showing columns, trusses, roof bars, vents and doors
Better Farm · design model One bay set in the model, doors included. They are drawn with the structure, in the gable glazing line, rather than cut into it afterwards.

Why insulated

An uninsulated metal door in a heated glasshouse is a cold bridge with a person standing next to it. It condenses on its inner face, drips on the floor it opens onto, and in a northern winter it is a measurable heat loss at exactly the point where staff spend their time.

Insulating the leaf also stabilises the climate near the entrance, which is where a climate computer's sensors are most often disturbed and where crop performance at the end of a row first shows a problem.

The door as a biosecurity boundary

Screening the roof vents at mesh 40 is pointless if the same insects walk in through a door that stands open while a trolley is unloaded. The entrance is the weakest point in a screened house, and it is weak in a way no single component fixes — it is a sequence problem, and the door set is specified as a sequence rather than as three separate holes.

Diagram An opening, or a boundary

  • One door While it stands open, the screened vents are beside the point: whatever is outside walks in.

  • An airlock A small lobby with a door at each end, and a mat on a floor that drains. A few square metres at the gable buy the most effective biosecurity in the house.

  • Slide, not swing A three-metre leaf on hinges is a sail in a crosswind and sweeps floor the crop needs. A slider stays in its track.

The same three doors, arranged so that the large one opens rarely and never straight into the crop.

Two doors, not one. An airlock — a small lobby with a door at each end, only one of which is open at a time — is what turns an opening into a boundary. It costs a few square metres at the gable, and it is the single most effective piece of biosecurity in a greenhouse. The loading opening sits at the service end, where there is room for one between the door and the growing area.

Size the personnel door so the large door stays shut. The 1,200 × 2,400 mm door is the everyday route precisely so that the 3,000 × 3,000 mm slider is opened for vehicles and pallets rather than for people. A large door propped open because it is the convenient way in is a hole in the envelope for the whole working day.

The floor at the threshold is part of the specification. A disinfection mat needs somewhere to sit that drains and can be cleaned. A threshold that ponds is a threshold nobody uses properly.

And the door is where the climate computer is misled. A cold zone at the entrance, where staff spend their time and sensors are often mounted, tells the control system something untrue about the rest of the house — one more reason the leaf is insulated.

Reference

Specification

Parameter Typical range
Openings
Vehicle door 3,000 × 3,000 mm, sliding, insulated aluminium
Staff door 1,200 × 2,400 mm, insulated aluminium
Loading bay Aluminium shutter door, at the loading and storage area
Construction
Hardware Rollers, rails, handles and seals supplied with each door
Frame Aluminium, set in the gable glazing line
Entrance sequence
Daily traffic Through the staff door, so the vehicle door stays shut
Loading At the service end, with room for a lobby before the growing area

Values for the standard Better Farm bay set, referenced to the governing codes. Project values are confirmed against the site's wind, snow and seismic figures, the crop and the equipment schedule before fabrication is released.

Design notes

What decides the detail

  • Slide, do not swing

    A three-metre leaf on hinges becomes a sail in a crosswind and sweeps floor area the crop needs.

  • Small door, big door

    Sizing a personnel door for routine traffic is what keeps the large opening shut, which is what keeps heat in and thrips out.

  • Insulate the leaf

    An uninsulated door condenses on its inner face and drips where people stand. It is also the cold bridge nearest the climate sensor.

  • Plan the vestibule

    Screening the vents and leaving the doors unsequenced protects nothing. The entrance sequence is part of the pest programme.

Reference

Common questions

  • What doors does a commercial greenhouse need?

    Three, and they do different jobs. An insulated aluminium sliding door of 3,000 × 3,000 mm for machinery and bulk movements; an insulated personnel door of 1,200 × 2,400 mm for everyday traffic, so the large door stays shut; and an aluminium shutter door at the loading and storage bay sized to the vehicles that use it. All are supplied complete with rollers, rails and hardware and framed into the gable glazing line.

  • Why are greenhouse doors sliding rather than hinged?

    Wind and floor space. A three-metre hinged leaf behaves like a sail — a crosswind across an open gable will pull it out of someone's hands and can tear the hinges — while a sliding leaf stays in its track under the same pressure. Sliding also costs no swept floor area to operate, which matters where the crop starts within a metre of the wall.

  • How do you stop insects entering a greenhouse through the doors?

    Screening the roof vents is undone by a door left open while a trolley is unloaded, so the entrance has to be treated as a sequence rather than a component. The answer is an airlock — a small lobby with a door at each end, only one open at a time — which turns an opening into a boundary for the cost of a few square metres at the gable. Alongside it, the personnel door is sized so that the large sliding door stays shut except for vehicles and pallets, and the threshold is detailed so a disinfection mat has somewhere to sit that drains and can be cleaned.

  • Why are greenhouse doors insulated?

    An uninsulated metal door in a heated glasshouse is a cold bridge with a person standing next to it. It condenses on its inner face, drips onto the floor it opens onto, and in winter it is a measurable heat loss at exactly the point where staff spend their time. Insulating the leaf also stabilises the climate near the entrance — which matters more than it sounds, because that is often where a climate computer's sensors are mounted, and a local cold zone tells the control system something untrue about the house.

Also relevant

Send us the site, the crop and the climate file.

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