The principle of ground screws
What it is
Section titled “What it is”A ground screw — also called a screw pile or helical pile — is a steel element that is driven into the ground rather than dug in or concreted.
Its capacity comes from two effects:
- shaft friction along the shaft,
- the resistance of the soil beneath the helix or plate (in compression) or above it (in tension).
Why it suits a light structure
Section titled “Why it suits a light structure”It works in tension too
Section titled “It works in tension too”The most important point. In a light building wind suction produces uplift, and a ground screw can take that by its nature — the mass of a shallow concrete foundation is not always enough for it. Resisting uplift in light structures.
No wet trades
Section titled “No wet trades”No concreting, no curing time, no weather-dependent stage. That suits the dry, fast logic of building.
Installation is a matter of hours or days, not weeks.
Little disturbance
Section titled “Little disturbance”Little earthwork, little spoil to remove — a serious advantage in a sensitive environment or among trees.
Removable
Section titled “Removable”The element can be unscrewed, so it can be used for temporary structures and buildings meant to come down again. That also suits a circular approach.
What it takes
Section titled “What it takes”Knowing the ground
Section titled “Knowing the ground”The capacity depends on the ground — far more directly than with a raft. So the ground investigation cannot be skipped here. Ground investigation report.
Installation torque is information
Section titled “Installation torque is information”The torque can be measured during installation, giving feedback on the ground and the expected capacity. That is one of the method’s strengths: installing each element is also a check.
Corrosion
Section titled “Corrosion”The element sits in the ground, so corrosion protection and the design life are linked. That is a question of material choice and design.
Verification
Section titled “Verification”The technical assessment belonging to the product used, together with the design, provides the verification.
The situation in Hungary
Section titled “The situation in Hungary”Screw piles are less widespread in Hungary than in the English-speaking countries, where the technology has a long history. Hungarian professional literature has been covering it in more detail in recent years, with case studies.
The point
Section titled “The point”A ground screw is not a “quick foundation” but a geotechnical structure. It is best where tension has to be resisted and where dry, fast construction is an advantage.