In this case, the putty should be hot, it will need to be laid in the cracks tightly enough so that the floor is as even as possible. After the putty has cooled and hardens the floor surface will need to be polished so that it becomes more even and smooth. By the way, it will not be superfluous after the repair to visit the cottage and start building a bathhouse there, or you can buy a ready -made bath here .