Frequently asked questions

The capacity depends on the model class, the type of soil and the installation depth. The range covers four load ranges: light (T1-T3) for single fixings, medium (T4-T6) for solar and light construction, high (T7-T10) and very high (T15) for infrastructure. The T15 models with Ø90 and Ø114 shafts reach uplift capacities of tens of tonnes in compact soils. Use our configurator to work out the capacity of the right model for your project to the Italian NTC 2018 standard.

Hot-dip galvanized to ISO 1461, their service life depends on the zinc thickness and on how aggressive the soil is. The zinc layer protects the steel from corrosion. For aggressive soils (high salinity, extreme pH) stainless steel is considered.

Yes. Ground screws can be used in seismic areas; the check is done on the project, to the Italian NTC 2018 standard.

In most applications, yes: fences, decks, garden sheds, carports, solar, signage, temporary structures. For very heavy buildings or in special ground conditions, we always recommend a project-specific engineering check.

Yes, the double-tube models with a hexagon head up to 60 mm and a moderate length can be installed by hand with a socket or a dedicated wrench: two people and 5–15 minutes per screw are enough. Larger models need a high-torque driver or a hydraulic rotary drive on an excavator. See the accessories section to choose the right equipment.

By hand: 5-15 minutes per screw. With a mini excavator: 2-5 minutes per screw. A 4x4 m deck on 9 screws is finished in under 2 hours. A solar installation with 100 screws in 1-2 working days.

Yes, this is one of their defining features. The screws are removed the same way they were installed (anticlockwise). Unscrewed, they leave no trace in the ground. Screws recovered intact can be reused over several cycles.

It depends on the model and the size of the job. The light models are installed by hand with a socket or a dedicated wrench, with no machine at all. For faster installation or larger-diameter models, a high-torque electric driver is used (light equipment, no excavator). On large jobs a hydraulic rotary drive is fitted to a mini excavator or a tracked machine. All the specific accessories are available in our catalogue.

Yes. Unlike concrete, which needs temperatures above 5°C to cure, ground screws are installed all year round, even in rain or frost. There is no curing time.

Ground screws work in almost every type of soil: clay, sand, gravel, mixed soils, silt, peat, frost-susceptible ground and slopes. There is a specific model optimised for each type of soil. In compact or hard ground a pilot hole is recommended, to keep the screw vertical and make screwing in easier; in rock, work is done after a technical assessment, with pre-drilling. Only very loose sandy soils can do without a pilot hole.

Yes, ground screws are particularly well suited to sloping ground. Each screw can be installed to the depth needed to take up the difference in level, with no need to level the ground or build retaining walls.

This is one of the cases where a screw foundation offers the biggest advantage: it needs no excavation that could damage the roots, and its footprint in the ground is limited to a single point. Compatibility with protection rules must still be checked case by case with the local authority and with the arborist or designer in charge.

Ground screws also work well with a high water table. The screw needs no open excavation that could flood. The capacity is calculated taking the water pressure into account, with Terzaghi's effective stress formula.

On average, ground screws cost 30-50% less than conventional concrete foundations, taking the total cost into account (materials + labour + time). Most of the saving comes from much shorter installation times and from doing away with excavation and spoil disposal.

Prices are given on quotation, based on the model and the quantities. Tell us about your project from the contact page, or make a first estimate with the online configurator: we will reply with a tailored proposal.

It depends on the structure you build on top, not on the foundation itself. A screw foundation is removable: for light structures (fences, carports, decks, pergolas) the procedure is often simpler, but how the works are classified depends on the project and on local regulations, so always check with your local authority or with the engineer in charge. For residential or commercial buildings the ordinary building regulations apply; in Italy the foundation is designed to the NTC 2018 standard.

Yes. Screw foundations (helical foundations) fall within the scope of the Italian building standards (NTC 2018). We provide the designer with the data and the calculation report for the model.

Yes. T-Block has a direct reference with the Italian Civil Protection Department for anchoring inflatable tents and emergency tensile structures. Speed of installation and removability are essential in emergency applications.