Q: I am ready to begin the repairs to my house and as I have started looking for a contractor I am learning that I also need to hire a engineer to monitor the work. Why do I need both?

Both have different roles and are independently important. The contractor is the one who actually does the work. They order and deliver the materials necessary (grout, chemical grout or underpins), supply the crew and materials and install the materials. They will pre-drill if necessary and pump the concrete into the ground and/or attach the underpins and drive them into the ground. The will often track much of the data such as amount of grout at each location etc. The contractor is not an expert per se and can not change plans. The engineer who monitors is an expert and licensed professional. The engineer can draw up and modify repair plans as necessary. The monitor will also check the mixture of the grout being used or verify the materials going into the ground and in general verify that the contractor is complying with the repair plans as drawn up. Think of the engineer or monitor as the architect and the repair company as the construction crew sent out to build the house he designed. Most often people will use the engineering company hired by the insurance company to monitor the work. They did the original testing and drew up the original plan. Sometimes however a homeowner may want to hire another engineer for various reasons. They may not trust the insurance companies engineer, may have gotten the insurance company to agree to pay for a different repair plan that their engineer did not draft or they may have settled a claim with the insurance company and need to hire a whole new engineer to do the work post-settlement. For these people it is usually best to hire a contractor that has an engineer on staff. A lot of foundation repair companies employ an engineer who can do the monitoring services. This not only makes it easier but also may save you money.