U&M Group

Why Is Piling Used?

Wednesday, October 25th, 2017 AT 02:57PM

If your home or commercial property is having problems with subsidence, you may be advised that one of the solutions to remedy this is piling. Perhaps you have questions like why piling is required, how does piling work and how to do piled foundations work, so here’s a brief outline of the subject.

When Is Piling Used?

Some cases of subsidence can be cured by methods such as removing tree roots or repairing drains. However, if the problem is more endemic, such as weak soil or old mine workings, the foundations will need to be underpinned. There are various techniques of underpinning, but piling is the one that’s most often effective if the ground would otherwise require deep excavations. In the main types of piling, concrete piles are driven or bored down to a more stable level, allowing the weight of the structure to be spread between them.

Piling isn’t only used to underpin existing foundations, though. It can be used in a wide range of new construction projects, ranging from erecting a domestic or commercial building on weak soil to supporting large structures like bridges.

What Are the Benefits of Piling?

A building without piles may be fine, if it’s built on strong, solid, stable ground. If there’s any weakness, though, the structure may begin to suffer from subsidence, resulting first in cracks in the walls and around doors and windows, and finally, in extreme cases, in complete collapse if the problem isn’t tackled.

Underpinning in general is to secure the foundations and redistribute the weight of the building onto strong stable ground. Piling achieves this not only more quickly and with less disruption than other methods, but in most cases more effectively. If the ground is very weak and prone to collapse, simply adding an extra layer to the foundations may not be enough, whereas the piles will be anchored in a stronger layer and make the building far safer. Piled solutions are also markedly environmentally friendly when compared to more traditional solutions, they create less spoil and use less concrete.

How Is Piling Done?

There are several approaches for how piling is done, each of which can be the best approach depending on the building, the ground and the space available. Broadly, though, the choice is between driving and boring the piles.

Driving, which tends to be the best option for soft, squeezing or granular soils, involves the piles being forced down into the ground, often by a Drop Hammer piling rig or Grundomat machine which uses compressed air to hammer each section of the pile down. Alternatively, the pile can be driven by transferring the energy directly to the pile toe, allowing for less bulky machinery that can be used in a confined space.

Boring or augured piles, on the other hand, involves drilling a hole which can then be filled with concrete or grout to create the pile. This can be done, for instance, with a continuous flight auger, which supports the sides of the hole till the grout can be injected, used when ground water is present. In general, boring creates less vibration than driving and requires less headroom, so it can be used easily in confined spaces and built-up areas.


If you have a foundation without piling that you think may need strengthening, why not give us a call to discuss your needs.