There are two ways to look at a major home repair. One way is by the amount of work involved, and the other is by the repair expense. Often, significant repairs are both costly and time-consuming but not always. For example, replacing a roof or raising a house to repair the foundation is labor-intensive, expensive, and can take several days or more. On the other hand, replacing a furnace can be done in a day if no additional work is required, but it is still expensive. Major home repairs to the exterior that are time-consuming would be replacing a roof, a new well, and septic, repairing foundation walls, replacing siding, and repairing sewer lines. Interior repairs that require a lot of work can be repairing water damage, removing mold, replacing a heating or cooling unit, extensive plumbing work, or replacing the electrical system. All these types of repairs usually require licensed tradespeople to complete and may require special equipment as well.