Underpinning the Situation
Underpinning is the method that is used to make the foundation of a building or structure stable. This process is carried out when a new building is being constructed, an existing building is being changed or the supporting soil has undergone changes. This could be due to the roots of trees growing and disrupting the foundations. If a nearby building has lower foundations then surrounding structures may need to be lowered to ensure its stability. Foundations may also be widened in certain situation to make them more supportive.
Underpinning is skilled work and must always be carried out and/or supervised by a qualified engineer. It is important to follow health and safety guidelines as it can be dangerous work. There are different types of underpinning available. Beam and base underpinning involves the construction of a concrete beam above or to replace an existing footing. The beam then transfers the weight of the structure to concrete bases.
The option of mini-piled underpinning is suitable for when foundation loads require to be transferred to stable soils at depths of more than 5.0 metres. The mini-piles can be either augured or driven steel cased and implemented using specially designed rigs.