Micro piles are smaller diameter foundation piles which are used in difficult ground and working conditions, such as where there are space constraints or underground boulders or rocks. They are widely used in underpinning, which provides additional foundation support to structures, and in upgrading and retrofitting.

As the name implies, micropile is small diameter piles constructed by the drilling process and are often keyed into rock. The diameter of micropile can be found in the market ranging from 100mm to 250mm. Of late, technological advancement in machinery has made it possible for micropile of much greater diameters to be constructed.