Few buildings will last without solid strong foundations, and various foundation types are best suited to different situations. Increasingly in recent decades, the technique of choice has tended to be piled foundations, largely driven by innovation as well as increased costs in spoil removal and concrete (as well as the environmental considerations).
What Is Piling?
Piling is a very old construction method, but recent improvements in techniques and equipment have made it the most popular approach to foundations. It involves inserting long columns, either in situ or pre-cast, usually of steel or concrete, into the ground. These reach a strong layer of either soil or bedrock, allowing the weight of the building to be securely distributed down to this solid level.
Piling can be used for large structures, particularly when they’re built in water (wind turbines, for instance), but one of the most common uses is for strengthening existing foundations. For this process, known as underpinning, mini-piling is often used. This technique is also very suited to new house foundations or extensions where access for larger CFA rigs is an issue.
What Are the Types of Mini-Piles?
There are broadly two types of mini-piles — bored and driven. For the bored type, the machinery removes the earth and inserts sections to support the side of the hole, if required. When this is complete, steel reinforcement cages are inserted (dependent upon the design) and grout is poured or injected to form the permanent pile.
Alternatively, ready-made piles can be driven straight into the earth, displacing the soil around them. This has the advantage of compacting the soil surrounding the pile, making it stronger. The method used will depend on issues like the quality and type of ground conditions and working conditions on the surface.
What Does the Piling Contractor Do?
Before anything else can happen, it’s essential to examine and assess both the site in general and the soil in particular. Issues like the strength and type of soil, the level of the water table, headroom if the piling will take place in a confined space and access to the site will all affect the type of pile best suited and the machinery that can be used.
After detailed plans have been made, the contractor will bring in their piling experts and machinery. This is one of many reasons why using a specialist piling contractor is important since they will have these resources available, rather than having to hire them in.
The piles will then be inserted, by whichever method has been chosen as the most appropriate. For mini-piling, this will often mean restricted access piling rigs, that have remote power packs considerably reducing the amount of site space required. A professional piling contractor will clear up and make good the site when finished. If you want to know more about piling, feel free to get in touch with us.