What is Piling?
Piling is the process which is used to build deep foundations by burrowing columns of concrete, steel, or wood into the ground to support asymmetric or heavy structures. These columns assist in transferring the building’s weight evenly on the deep layers of ground.
Piling is needed if the existing soil conditions are not stable or if there is a high-water level which may impact the soil beneath your property’s structure. It is a major and crucial part of your project, for which careful budget planning is required. The cost of different types of piling is different, so you need to have an idea of the costs so you can budget accordingly based on the type of piling required for your building project.
This guide provides information about piling, factors affecting the cost of piling foundations, and the cost of different types of piling techniques.
Factors Affecting the Cost of Piling Foundations
There are certain factors which impact the cost of building piling foundations, such as:
Foundation Size: The cost of piling is directly related to the size of the foundation, as more piles will be required to form foundations at a large scale for an even distribution of weight, which requires more investment.
Piles’ Depth: The depth of piles is decided based on the type of building to be constructed. For example, high-rise buildings will require stronger and more durable foundations at a greater depth. Therefore, boring deeper piles requires more cost.
Piling Type: Different types of piling techniques are used for different projects, and every technique has its own process and labour requirements, which impact the cost requirements accordingly.
Site Access: Some construction sites are easy to access; however, others have restricted access that requires specialised equipment and piling methods, which significantly increases the cost.
Soil Conditions: The construction work is carried out slowly in challenging soil conditions and requires specialised practices for installing piles, which ultimately leads to increased costs. It also includes performing geotechnical tests to assess the soil conditions, which also demands a significant cost.
Cost of Different Types of Piling
Bored Piling
This piling technique is used at construction sites with lose ground conditions, particularly in urban areas where buildings are close to each other. The soil is removed using drilling tools and augers to achieve the required depth. After that, piles are constructed in situ using specialised rigs. On average, the cost of bored piling varies from £200 to £400 per linear metre.
Driven Piling
This type of piling method is mostly used in contaminated soils or areas with a high-water table. Hydraulic hammers or vibrations are used to drive pre-cast piles into the ground. The cost of driven piling ranges from £150 to £300 per linear metre.
Mini Piling
In this technique, building foundations are formed by using mini piles with a smaller diameter. These piles are lightweight and cheap but can safely carry a significant amount of load. During mini-piling, a hollow shaft of steel is drilled into the ground, and then concrete is poured, which provides the necessary support to the pile and eliminates the requirement for additional supports.
On the other hand, sectional auger mini piles are also used in some cases when there is restricted access or limited headroom at a construction site. The cost of mini piling ranges between £50 and £100 per linear metre.
Saltwater Piling
It is rather an old piling technique in which timber is used for holding up the dock. The piles provide vertical support, which is used for anchoring and supporting the dock, piers, or other kinds of waterfront materials. These are driven into the ground and help to ensure the security and stability of water structures against the constant water movements and tides.
The cost for saltwater piling ranges from £20 to £50 for a 20-foot-long pile.
Screw Piling
These types of piles can be easily screwed into the ground, and this type of piling is being used for residential purposes to build extensions, garden outbuildings, etc. It is a cheap and quick method that involves fewer disruptions with reduced mess at the construction site. The cost of screw piling can range from £45 to £300.
Sheet Piling
In this technique, sheets with interlocking edges are used for burying into the ground, which helps in retaining Earth or supporting excavations. The sheet piling method is suitable for commercial buildings to carry out construction work on a larger scale. These sheets can be made of plastic or steel:
Steel Sheet Piling: Steel sheet piles are strong, watertight, and resilient to stress, which makes them suitable for retaining wall construction. This piling technique can be conveniently used in areas with water, such as riverbanks, seawalls, etc.
Plastic/Vinyl Sheet Piling: These types of piles have a long lifespan and are easier to handle because they are light in weight. Plastic or vinyl sheet piles are also easy to carry to hard-to-access construction sites.
The cost of sheet piling falls somewhere between £100 and £200.
Concluding Remarks
You can carry out construction work on unstable ground conditions with the help of piling. The type of technique being used greatly impacts the cost of piling and holds a significant percentage of your construction project’s overall budget. Different piling techniques have different costs due to specialised processes and machinery used in each method. Moreover, this cost also varies based on the project’s complexity, depth, and size.
Therefore, you should carefully plan your budget for piling based on your project’s unique requirements.
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