I bet you didn’t realise that there was such a thing as soft polished concrete floors! Often a standard concrete slab can be well below the strength required for a polished finish to our high standards. Strength is more to do with water to cement ratio than how much steel mesh is used.
Whenever we’re asked to work on an existing concrete floor, it’s one of the first things that we need to check before finalising any quotation as soft concrete is far more abrasive to our tools than harder concrete and always requires more attention; for example when filling surface voids.
Usually softness of the concrete is down to adding too much water to the mix during installation. We have however encountered floors becoming softer through the underfloor heating being commissioning incorrectly.
To increase the hardness of the concrete floor we need to use chemical densifiers to create a chemical reaction that strengthens the floor surface enough to work with. The process of adding chemcial densifiers is labour intensive and time consuming.
A soft concrete slab inherently contains more air pockets and less dense than a strong well compacted slab, this affects the performance of your underfloor heating and may retain heat more than it should. Strong dense concrete is a good conductor, a slab full of air is not quite as effective.
The less strength in your poured concrete, the less glossy finish you can achieve in the finished look and less easy to clean. More chemical densifier application means your should expect to pay more per m2. An existing concrete floor can often be quite expensive to work with.