In recent decades, piling has become the method of choice for the majority of underpinning needs. Compared with other methods, it’s quicker, less disruptive, requires less concrete and spoil disposal and is therefore much friendlier on the environment. It can also provide ‘stronger’ underpinning in more poor-quality soils.
What Is Piling?
Piles are either metal or concrete shafts which are inserted into the ground to distribute the load of a structure down to a secure sub-surface layer. They’ve been traditionally used for building large structures, but piling is now widely used in underpinning solutions, although more traditional methods still have their place.
Piles can be either driven straight into the ground or concrete poured into drilled holes. Both systems have their advantages and disadvantages, and one is usually recommended for a given project and ground condition.
Why Use Piling?
If your home is at risk of subsidence, it may need to be underpinned. This could be because the soil quality is weak, there’s a high water table or there are old excavations beneath it.
Piling has the big advantage over other methods of underpinning that the piles reach down much further into the ground. This means they can be anchored in a stronger layer, redistributing the weight of the building down to a level that can hold it.
At one time, the disadvantage of piling was that it required large, disruptive machinery, which wasn’t practical in a domestic building. Modern mini-piles, however, use far more manageable machinery that causes relatively little disruption.
What Are the Types of Piling?
Broadly, piling can be divided into two types. Driving piles, which can focus the power either at the top or toe of the pile, is best suited to soft, squeezing soil. Among the options for driven piles are:
- Steel Cased Bottom Driven Piles, where the energy is delivered directly to the toe, are an extremely efficient system. This means the machines can be relatively small, so this approach suits confined spaces.
- Steel Cased Grundomat Driven Piles are powered by compressed air. Sections of casing are inserted and welded together, causing less vibration than other forms of driving.
With augered piles, a hole is bored first and then filled with (reinforced) concrete or grout to make the pile. This tends to have the advantage of causing less vibration than driving. Options include:
- Sectional Auger Mini Piles are very versatile, especially in restricted spaces. Here, multiple flight sections are inserted.
- A Grout Injected Continuous Flight Auger is drilled in a single flight or hollow stem. This supports the sides of the hole throughout the process.
- Helifix Dixie Pile which is a helix ‘screwed’ into the ground providing end bearing capabilities under each helix
If you want to know more about how piling could help you, feel free to give us a call.