Having work done in the construction industry can be a complex undertaking. You have to find a contractor who can get the project done, and you have to find terms that are negotiable to both sides. In most cases, there are going to be adjustments to the terms of the contract when you are working through the project. These alterations are usually relayed through change orders.
The foundation of a building is meant to last the life of the structure. When there are issues with the foundation, there is a good chance that the entire building can suffer. In the most extreme cases, the structure might lean or fall.