Measuring Torque During Screwpile Installation

When it comes to installing screwpiles, monitoring the torque is one of the most important steps in making sure your foundations are up to the task. Simply put, the torque reading tells us how much resistance the ground is giving as the pile is screwed in. That resistance helps us determine whether the pile will support the loads it’s designed for.

To be confident that a pile will perform well under load, it must reach a calculated torque value during installation. This is how we confirm that the pile is securely anchored in suitable ground conditions. In addition, it's essential to meet minimum depth requirements during installation—specifically, the first flight of the screw pile must be at least 2 meters below ground level. This ensures proper embedment and resistance to uplift forces.

How Do You Measure Torque?

Torque is measured in real-time using a gauge fitted on the torque head, whether it's a handheld model or mounted on an excavator. The operator can see the torque reading as the pile is driven into the ground, allowing for immediate feedback and adjustments if needed.

How Is Torque Related to Load Capacity?

There’s a well-recognised formula that links torque to the ultimate uplift and compression capacity of the pile. It works the same way regardless of whether you're using a handheld or machine-mounted system:

Qu = Kt × T

Where:

Qu = Ultimate uplift capacity of the pile (kN)
Kt = Empirical torque factor (m-1)
T = Average installation torque (kNm)

What is Safe Working Load (SWL)?

Safe Working Load (SWL) is the maximum load a pile or anchor can safely support during everyday use. It’s calculated by dividing the ultimate load capacity (the maximum it can theoretically withstand) by a safety factor, which accounts for uncertainties like soil conditions and real-world loading.

The appropriate safety factor – and therefore the SWL – should always be confirmed by a structural engineer. However, based on our experience and industry knowledge, a typical safety factor is usually between 2 and 3, giving an estimated SWL range that’s both practical and secure.

Example Calculation:

Ready to build on a solid foundation? Here's how your trusty 60R screw pile gets the job done like a pro!

The Dream Team Setup:

Lead the way! Start with a 2m lead section, fitted with a double helix – that’s 8” and 10” plates spinning their way deep into the ground.
Need a little extra? Add a 2m extension if the ground’s playing hard to get and you haven’t quite hit the target torque.
Top it off! A termination plate will be added (we’ll confirm the exact type based on your setup)

How Deep and How Much Torque?

Depth goal: At least 4 metres below where you want the pile to finish.
Torque target: Hit 4000 Nm and you’re golden!

This combo makes sure your pile can handle the pressure, literally.

Crunching the Numbers – The Super Strength Formula:

We use this handy little formula to work out how much weight your pile can hold:

Qu = Kt × T

Where:

T = Installation torque (in kNm)
Kt = Torque factor (it’s 30 for the 60R pile)
Qu = Ultimate load capacity (in kN)

So, for your pile:

Qu = 30 × 4 = 120 kN
That’s the ultimate strength per pile.

What Can It Safely Carry?

With a safety factor of 2–3 (just to be extra cautious), each 60R pile gives you a Safe Working Load (SWL) of around:

40–60 kN per pile

Whether you're holding up a garden office or a grand design, these piles have your back.

Installation FAQs

What torque value do I need to achieve for my pile installation?

The required torque is based on your load requirements and soil conditions. Your torque target will be in your pile design or specification document. As a rough guide, the torque-to-load ratio is typically 10:1 (i.e., 10 kNm torque = approx. 100 kN compression capacity), but we always tailor this to your specific project.

What if I exceed the required torque before reaching the design depth?

If you hit torque early, that’s usually a good sign — the soil is offering more resistance than expected. You may not need to go deeper, but stop and contact us and we can advise next steps.

What if my pile is spinning or not advancing?

This may be a sign of:

Obstruction (e.g., large rock, buried debris)
Incorrect or blunt pile tip
Insufficient downward pressure

Solution: For obstructions, you may need to reposition the pile or pre-drill. We can guide you on changing technique.

Do I need to galvanise my piles?

We recommend galvanising the top 2 metres of each pile if long-term corrosion protection is needed — especially in damp ground or where piles are near the surface. This ensures a life expectancy of 100+ years in typical UK soil conditions.

What torque heads do you recommend for installing piles?

We offer both hand-held and machine-mounted torque heads. The right choice depends on your pile size and access conditions:

For 60R piles or tight access areas: try the 400H or 700H hand-held units.
For larger piles or deeper installations: we recommend Autoguide’s hydraulic torque heads (e.g., 1200X, 1500X).

Need help selecting a head? Get in touch and we’ll guide you.

How do I know if the pile is fully installed?

You’ll know your pile is installed once: you have reached torque.

Record torque readings during installation, especially for building control or warranty providers.

Can I reuse a screw pile if I remove it?

Yes — screw piles are often reusable if removed carefully and not damaged. Let us inspect the pile before reuse to confirm it’s structurally sound and still meets requirements.

Can I install screw piles in bad weather?

Screw piling can often continue in wet or cold weather, unlike concrete foundations. However, access, visibility, and safety must be considered — particularly if you’re using machinery.