Polytunnel greenhouse with a green sheet fitted on a base frame resting on T-Block ground screws, on a lawn.

Ground screws for greenhouses and polytunnels, without concrete

From the small vegetable-garden greenhouse to the multi-span agricultural tunnel, the structure is fixed on T-Block^® ground screws screwed into the soil. No digging and no pouring: it goes up straight away, holds against the wind and is unscrewed at the end of the cycle.

Up to 12 m

span, from the vegetable-garden greenhouse to the industrial tunnel

No footings

no concrete goes into farmland

They unscrew

at the end of the cycle, and the field stays workable

From the vegetable-garden greenhouse to the industrial tunnel

Family greenhouse

Light arches on a perimeter base, T-Blocks installed by hand.
Agricultural tunnel

Long tunnels, points in a row: the T-Block tracked machine installs them one after another.
Industrial tunnel

Large-span lattice arches, mounted on T-Blocks.
Large structures

Columns with a plate bolted to the T-Block flange.

A range for every structure

From the vegetable garden to the industrial tunnel, in hot-dip galvanized steel. Outside the catalogue, custom models.

structure classes, from the greenhouse to the multi-span

catalogue models for greenhouses and tunnels

495–3000

mm in length, from 2 to 12 flights

installation methods: by hand, power driver, excavator, tracked machine

How to anchor a greenhouse or tunnel to the ground: the four systems

Each system has its place. What matters most in choosing is how much wind the structure catches and what the soil is like.

Stakes

Pros: Cheap and pushed in by hand.

Limits: They hold by friction: fine for light greenhouses and compact soils. On large tunnels or in soft soils the wind pulls them out.

Ballast

Pros: No digging: blocks, sacks or barriers laid on the ground.

Limits: They hold only with their own weight: a tunnel needs big weights, which clutter the edge of the field.

Concrete footings

Pros: They hold well, even large structures.

Limits: Digging, pouring and waiting for the concrete; at the end of the cycle they stay in the ground and have to be demolished.

Ground screws

Pros: They work in tension: to come out they would have to lift the cone of soil above the helix. They take load straight away and are unscrewed at the end of the cycle.

Limits: They are chosen according to the soil and the loads; in rock another solution is needed.

In a tunnel the wind pulls upwards

A tunnel weighs little and catches a lot of wind. When the wind passes over the arch, a low pressure forms on the sheet and pulls it upwards, as happens to a wing; on the exposed side the wind pushes sideways.

That is why the foundation of a tunnel has above all to hold down: resist uplift and lateral thrust, more than carry weight.

T-Block^® works like this: to come out it would have to lift the cone of soil above the helix. The longer it is and the more flights it has, the more soil it engages: that is why on large tunnels and in windy areas you go up a series.

Which T-Block for which greenhouse or tunnel

The larger the structure and the more exposed it is to the wind, the longer the T-Block and the more flights it has. All models are in hot-dip galvanized steel.

1. Small vegetable-garden greenhouse

Light frame in tube or timber. The round upright slots into the headless T-Block; frame bases are fixed onto the hex head.

Installation: By hand

2. Family polytunnel greenhouse

Light arches on a perimeter base: the base is fixed onto the hex head or the flange, the Ø48 arches slot into the headless T-Block.

Installation: By hand

3. Single-span agricultural tunnel

Ø60 tube arches, up to about 6 m wide: each arch foot goes into the headless T-Block for a Ø60 post, flush with the ground, and is locked with the three M12 side fixing points.

Installation: By hand

4. Large and industrial tunnels, up to 12 m span

Up to 12 m wide and over 7 m high: the foot has to resist the moment too. It is fixed onto a slotted flange with gussets, or onto a cross frame that ties several T-Blocks together under the column.

Installation: Excavator or tracked machine

5. Multi-span, large greenhouses, shade structures

Columns with a base plate, shade nets and anti-hail nets. The column plate goes onto the slotted flange: level to the millimetre, the slots absorb position tolerances.

Installation: Power driver with reaction bar (T7), excavator or tracked machine (T10)

The arch foot in small tunnels

In tunnels with Ø60 arches the headless T-Block^® acts as the sleeve: it is screwed in flush with the ground, the arch is slotted in and locked with the three M12 side fixing points. The connection is entirely mechanical, with no welding on site.

The M10 through hole is for the installation wrench. In large tunnels the foot is instead fixed onto a slotted flange with gussets or onto a cross frame.

Agricultural tunnel with a green sheet and, under the cover, the orange T-Block tracked machine screwing in the ground screws. — Long tunnels, identical points in a row: the tracked machine installs them one after another, even under the structure once it is already assembled.

Large and industrial tunnels, up to 12 m span

A range of models by tunnel width and soil. The exact model within the range is chosen on the project, with the real loads and soil.

Ranges of T-Block models by tunnel width and type of soil
Tunnel width	Loose soilsand, fill, soft clay	Medium soilsilt, farmland, gravel	Compact soilfirm clay, hard ground
Up to 6 mone T-Block per arch foot	T5 → T7	T4 → T6	T4 → T5
6 to 9 mridge height up to about 5 m	T7 → T10	T6 → T10	T5 → T7
9 to 12 m and large spanscolumns on a plate with several T-Blocks	T10 → T15	T7 → T15	T7 → T10
Special casesstrong wind, peat, fill, over 12 m	On project, with our technical office.

It is a starting hypothesis, not a calculation. With large spans between columns you get to the 3 m T15, as in the covers of tennis courts.

Four ways to connect it

T4 · M12
T6 · M16

Hex head

For bases, frames and ground beams: the bracket or plate is fixed in the threaded hole of the head (M12 or M16).

See the model

T4
T5
custom
sleeve

Ø60 sleeve

Only where the arch has to be slotted in, as in most greenhouses and small tunnels. T4 and T5 in the catalogue; longer ones, made to order.

See the model

T10 · Ø500
T15 · Ø500

Slotted flange with gussets

For large, tall tunnels: it also resists the moment at the foot. Level to the millimetre when installing; the slots absorb position tolerances.

See the model

Galvanized steel cross frame under a column, bolted onto the flanges of several T-Blocks screwed into fine gravel.

Cross frame on several T-Blocks

For large spans between columns: a cross frame ties several T-Blocks together under the same column.

The custom sleeve, in four steps

For Ø60 arches on the widest tunnels: a custom single-tube Ø60 T-Block and the sleeve accessory, locked with two bolts on the same axis for each connection.

1. Top of the custom T-Block: two holes on the same axis
2. The sleeve accessory
3. Accessory locked on the T-Block with two bolts
4. Ø60 post locked in the accessory

Where the T-Blocks go

One T-Block per arch foot: two aligned rows, one per side, at the spacing of the arches. Base rail: a ground-level section collects the arch feet and rests on T-Blocks at a wider spacing.

Large spans: under each column a cross frame ties four T-Blocks together.

Large tunnel with galvanized steel lattice arches being assembled on a hillside. — A large-span lattice-arch tunnel during assembly. If you sell or install greenhouses and tunnels, we can work together.

How it is installed: from the hand wrench to the excavator

Installation follows the size of the T-Block: by hand for small models, power driver with reaction bar for intermediate ones, excavator or tracked machine for the largest and for industrial installations.

Gloved hands on the T-handle, with the socket fitted on the head of a T-Block going into the lawn.

Small models · T3-T6

By hand

T-handle and a socket the size of the head.

Driver with a socket on the head of the T-Block and the reaction bar resting on the ground.

Intermediate models · T7

Power driver with reaction bar

High-torque driver, with the bar resting on the ground.

Large models · T10

Excavator

Hydraulic rotary drive on the arm, for the longest models.

Industrial installations

Tracked mast machine

Long tunnels and many points in a row, aligned one after another.

Anchoring and permits

Whether an agricultural tunnel needs a building permit depends on the municipality, on how long the structure stays and on how it is used: it must always be checked with your own municipality or with a technician.

What we can say is how the anchor is made: ground screws are removable, need no concrete work and are unscrewed at the end of the cycle without leaving a trace. It is an element that local regulations may take into account.

For a quote, send us

The loads on the T-Blocks: tension, compression, shear and moment.
The soil: what it is like (clay, sand, fill) or the geological report.
If you do not have the loads, for a hypothesis: how the structure is made (dimensions, arches, cover), the area and a few photos.

The calculation of the structure, and therefore of the loads on the T-Blocks, remains with the designer.

Request a quote A hypothesis with the configurator

Frequently asked questions

How do you anchor a greenhouse to the ground without concrete?

A T-Block ground screw is screwed in under each arch foot or under the base, and the structure is fixed onto its head. Small greenhouses are installed by hand with the T-handle wrench; long tunnels with the power driver or with the machine. There is no digging and no concrete: the greenhouse goes up straight away.

Are stakes enough for an agricultural tunnel?

For light greenhouses and in compact soils, often yes. An agricultural tunnel catches a lot of wind: above the arch a low pressure forms that pulls it upwards, and stakes, which hold by friction, can be pulled out. Ground screws work in tension: to come out they would have to lift the cone of soil above the helix.

How much wind can a tunnel anchored with ground screws take?

It depends on the loads of the structure and on the soil: that is why we first ask for the loads on the T-Blocks (tension, compression, shear and moment) and then for the characteristics of the soil. We choose the model and the spacing from that data. The calculation of the structure remains with the designer.

Is a permit needed for an agricultural tunnel anchored with ground screws?

It depends on the municipality, on how long the structure stays and on its use: it must be checked with your own municipality or with a technician. A removable anchor, which needs no concrete work and is unscrewed at the end of the cycle, is an element that local regulations may take into account.

Can they be removed at the end of the season?

Yes. T-Blocks are unscrewed anticlockwise, with the same tool used to screw them in, and leave no concrete blocks in the ground: the field stays workable.

Which T-Block for a tunnel 6, 9 or 12 m wide?

As a starting hypothesis: up to 6 m from the T4 to the T7 series, from 6 to 9 m from the T5 to the T10, from 9 to 12 m from the T7 to the T15, depending on the soil. With large spans between columns, several T-Blocks are tied together under the same column. The exact model is chosen on the project, with the real loads and soil.

More answers on service life, soils and permits in the FAQ.

The other applications in the fields are on the Agriculture page; for agrivoltaics there is the Agrivoltaics page, for fences Fencing without concrete. The full comparison is in ground screws or concrete.

Got a greenhouse or tunnel to anchor?

Send us the loads and the soil, or how the structure is made: we will suggest the right T-Block and confirm it on your project.

Request a quote How it works