Hi Neil, there are many variations come into play when using melamine floor cleaning pads, the thickness of the melamine being one of the main ones, standard melamine pads are produced using 8.2 kgs/cbm of melamine and will erase themselves very quickly, but if you look to use compressed melamine pads you can go up to 16.4 kgs/cbm these type are far more durable and a better choice if you are deep cleaning rough finish flooring, i have seen them in thickness of melamine from 11mm up to 25mm, i would always prefer to use the thicker size and heavier weight of melamine, hope that this helps, Tadgh