Whether flooring should go under cabinets depends on the type of flooring being installed. For any flooring that adheres to the floor, such as tile, and perhaps engineered hardwood depending on the type you choose, the flooring should go under the cabinets, forming a solid base for the entire kitchen. However, if you are installing floating floors that do not adhere to the ground, such as vinyl plank flooring or some engineered hardwoods, they should be installed after your cabinets are in. This is because the weight of the cabinets can restrict the floor from its natural expansion and contraction.