generaly with the proper buffing equipment and some diamond screen discs you can refinish the floor fairly easily although it does make a mess as all is done with water. this also depends on the damage. if it is just the wax and sealer that is scratched up then this is something a good maintenance staff should be able to do. if the scratches go beyond that it would need to be polished again and you're staff wouldn't have the proper equipment to do the job. and for the cost of the equipment it is cheaper to hire the job out at the cost of the construction company's due to the damage they caused.