Reuse of screw piles

When is the reuse of screw piles permitted

Reusing screw piles isn't always possible, but in some cases it is. The main condition is that the pile maintains its geometry, metal integrity, and blade functionality. If these parameters are within specifications, the pile can last for several more years.

Reuse is generally permitted:

•        Temporary structures. For example, pavilions, hangars, exhibition stands, and seasonal terraces. Such structures are often dismantled and reinstalled, making reuse of the piles entirely justified.

•        If dismantling is performed carefully. The pile should be unscrewed, not pulled out, otherwise the shaft may be deformed or the blade damaged.

•        When the pile's service life was short. If the piles have been in the ground for less than 1–2 years, the risk of corrosion and fatigue deformation is minimal.

•        If they have a factory-applied anti-corrosion coating. Hot-dip galvanizing or high-quality powder coating significantly extend the service life of the metal, even with repeated installation.

It's important to understand: reusing piles is not recommended for capital buildings, residential buildings, and critical structures. In these cases, any doubts about the condition of the metal are unacceptable—the stability and safety of the structure directly depend on it.

What factors influence the suitability of a pile for re-installation?

Before reusing screw piles, it's important to accurately assess their condition. Even if a pile appears intact, internal metal damage or geometric misalignment may only become apparent after reinstallation—when it's too late to correct.

Key factors determining suitability:

1. Corrosion and coating condition

If rust spots, chipped paint, or traces of moisture appear on the surface, reuse is undesirable. Internal corrosion of the shaft is particularly dangerous and cannot be seen without endoscopic inspection.

2. Blade integrity

The blade is the basis of the pile's load-bearing capacity. If it is bent, deformed, or cracked, the pile will no longer provide the required resistance to the soil. Repeated installation can permanently damage the metal.

3. Shaft straightness

Even a slight curvature will result in a shift in the vertical axis, meaning the load will be distributed unevenly. This is one of the most common errors during reinstallation.

4. Soil type and density

In loose or peaty soils, piles are removed relatively easily and are less susceptible to deformation. However, in clayey and rocky soils, the metal is subject to significant stress—after removal, microcracks that are invisible to the naked eye are possible.

5. Presence of mechanical damage

Welds, heads, and fastening points must be free of cracks, chips, and signs of deformation. Even minor damage can reduce the load-bearing capacity by tens of percent.

How piles are tested before reuse

Before installing screw piles again, they must be thoroughly inspected and tested. This step cannot be skipped—it determines whether the foundation will withstand the new load or fail within a season. The inspection includes several mandatory steps.

1. Visual Inspection

The first step is a visual inspection of the shaft and blade. Look for:

•        rust, cracks, dents, and signs of bending;

•        condition of welds and caps;

•        presence of soil or concrete residue on the surface.

Any defects are grounds for rejection. If a pile has even one significant bend or signs of severe wear, reuse is unacceptable.

2. Checking Straightness and Geometry

The pile must be straight—without any curvature, especially near the blade. This is checked using a level or straightedge. If the deviation exceeds 2–3 mm per meter of length, the pile is no longer suitable. 3. Wall thickness check

The metal can become thinner over time due to corrosion, especially in the area of ​​contact with soil and moisture. The thickness is checked with an ultrasonic device or a micrometer. If the layer becomes thinner than the specified thickness (usually less than 3.5 mm for household piles), the pile is replaced.

4. Test screwing

In some cases, a test screwing is performed on a site with a similar soil type. If the pile does not enter straight or exhibits play when screwed in, the blade is deformed and cannot be reused.