Impurity on the floor

When I was in my home many years ago semen got onto the floor (not tiles but smooth floor). I knew nothing about najaasat and all so I just wiped it off with dirty cloth and there was no trace of najasat over there then and later the floor was cleaned with wet cloth and the same cloth is used for cleaning the whole house. Does this make the whole house impure? And if so then the water on the floor which gets absorbed or dried make the floor pure again? If not what should I do now?