Screw Foundation

The foundation of any building or structure is its lower load-bearing part, serving as a support that withstands loads from both the entire upper structure and its own weight. Its reliability, strength, and durability guarantee high operational performance of the building.

Application of Screw Foundation

Modern technology for installing screw pile foundations can be used in constructing small and lightweight structures (dacha houses, saunas, greenhouses, etc.), as well as low-rise brick, panel, and block buildings. Screw foundations are also used in buildings constructed using frame, modular, and SIP technologies (thermal-insulated sandwich panels).

When other methods and technologies are not cost-effective or practically impossible, screw pile foundations help builders complete their planned projects. Their high reliability and strength allow construction on challenging soils (sandy, clay, peat) and in unfavorable climatic conditions.

Structure of Screw Foundation

The main component of such a foundation is a metal pipe with a conical tip and a welded attachment in the form of helical blades of a specific design. The pile is coated along its entire length with an anti-corrosion compound with high adhesion and mechanical wear resistance.

Installation Technology

Design. Based on expected loads, the minimum required diameter, number of piles, and spacing are determined.

Test Screw-In. By screwing in a specialized pile, soil type, properties, and quality are assessed. Results determine future foundation parameters and the optimal screw-in method: manual or mechanical.

Layout. Axis lines for the pile field are established.

Screw-In into Soil. This is the main installation stage. Depending on pile type, diameter, length, and quantity, installation is done manually (2–4 people) or with specialized equipment. Maintaining horizontal and vertical alignment during screwing is critical.

Leveling. Due to possible changes in soil structure, piles may be screwed in at varying depths. Therefore, installed piles are trimmed to a uniform level (as per design).

Concrete Filling of Pile Shaft. The pile shaft is filled with cement-sand mix to the leveling point, increasing metal corrosion resistance and enhancing pile rigidity.

Installation of Pile Cap. After cutting and concreting, pile caps are welded to the piles, designed for securing the tie beam.

Protection of Weld Joints and Caps. To prevent corrosion, caps and weld joints are coated with high-strength enamel or a special protective compound.

Advantages of Screw Foundation

The advantages of screw foundations contribute to their growing popularity. These include:

Fast construction and reduced labor costs within 1–5 days (depending on manual or mechanical screw-in method);
Ability to install during winter: due to additives in concrete, additional labor costs in winter, and shorter daylight hours, costs for other foundation types may rise significantly;
Simple and highly efficient construction process: no need for ground preparation;
No curing period required after installation, reducing overall construction time;
Minimal time and equipment needed for installation; no need for complex machinery or equipment;
Enhanced safety during installation, subsequent construction stages, and long-term building maintenance;
Long service life: treated screw piles can last 100–150 years;
Feasibility of installation on uneven terrain (e.g., slopes), problematic, marshy, and waterlogged sites, and on well-kept lawns without damage;
Longevity of wooden components due to free air access;
Ability to easily unscrew and reuse piles;
No need for major excavation, soil removal, or waterproofing.

Disadvantages of Screw Foundation

Disadvantages mainly relate to the material of screw piles—steel:

Steel’s tendency to bend under load (unlike reinforced concrete) may cause piles to slightly tilt under strong wind pressure. This could lead to minor shifts in the structure’s base, affecting joint strength, tightness, and the condition of interior and exterior finishes.

Necessity of using a reliable pile cap to connect piles. It is recommended to use strong I-beams or reinforced concrete, which inevitably increases foundation cost. Poor-quality pile caps (made from weak materials) may damage the foundation.

After calculating the minimum required diameter, the cost of pipes for pile fabrication may exceed standard pile prices. Therefore, installing such foundations on normal soils may not be cost-effective.

Potential damage to protective coating during screwing, leading to increased corrosion and pile damage.

Impossibility of installing a basement.

Additionally, screw pile foundation technology cannot be used on rocky terrain.

Screw pile foundations are most commonly used in constructing panel, log, and timber frame houses, as well as hangars, sheds, and utility buildings. They are convenient and cost-effective for docks, bridges, fences, and retaining walls.