House underpinning is the process of strengthening and stabilising the foundation of a house. It is usually carried out when the foundation — the base that the building stands on — is weak and unstable, and thus undermines the structural integrity of the entire building. The foundation itself may require underpinning service due to a number of different reasons. 

Here are a few common reasons why you might need the services of a house underpinning contractor.

Subsidence of the soil

Movement of the soil on which the foundation of a house has been laid is perhaps the most common reason why building owners require underpinning service. The soil might move because of a number of different reasons including natural causes like flash floods and earthquakes, operation of heavy equipment onsite, or major excavations close to the foundation of existing buildings. If soil movement causes the foundation of your structure to subside and become weak and unstable, you will need to call in an underpinning contractor to fix the problem.

Traditionally, mass-pour underpinning was used to strengthen the foundations of affected buildings. These days, however, there are better ways of getting the job done properly. Some of the newer methods of underpinning for buildings whose foundations have been weakened by soil subsidence include resin injection underpinning, pile and beam underpinning and underpinning with steel screw piles and brackets. Before deciding on which underpinning method to use, you should get a soil engineer to test your soil first.

Added structural load

If you are contemplating adding a second storey to your existing house, the original foundation might not be strong enough to support the weight of the extra storey. Even if the original foundation had been built strong enough to support the structural load of an extra storey in the future, the stability of the foundation may have dwindled over time. 

Therefore, you will need an underpinning services to help strengthen your existing foundation so that it can support the weight of the extra storey. Making the extension without first strengthening the foundation of the structure can compromise the structural integrity of the entire building, but also put you and other people in harm's way.

House underpinning is a job that is best handled by professionals because it requires a lot of knowledge, skill and experience to perform properly the first time, so don't hesitate to call in a pro when you need to have your house underpinned.