Do I really need to densify the concrete twice?

First & Foremost – Consult the Manufacturer of the Densifier!

Densifying the floorThe first answer that comes to my mind is to suggest that the manufacturer of the densifier needs to be consulted. The company that makes the densifier knows their product best and their instructions for using their product should be followed – implicitly!

STI makes no densifier so I cannot speak as a manufacturer of this product, but in my practical experience, the answer is a strong "maybe." Generally speaking, concrete is a mixture of many natural materials in various ratios depending upon the intended use of the concrete product. For the purpose of saving time, I'll just comment about concrete used for floors that will be polished and already are in place – new or old.

These concrete products are already at a point in their lifespan where the only thing that will influence their final appearance will be mechanical and chemical treatment. STI is an expert for the mechanical portion of the work, but I'll stick to the question and advise about the chemical work.


Is it better to buy a Propane or Electric P/M Machine?

propane-or-electricThe convenience of running a propane P/M Machine that is cordless does have its benefits as it requires no power from the work site. Assuming the machine is being run wet, it can be very productive having no required tethering to a dust collector.

The downside to a propane machine is that it is louder than an electric machine, has more maintenance requirements, requires good ventilation, and lacks the operative speed range of an electric machine.

The electric P/M Machine is exactly the opposite on all points.

For performance, either machine will do a great job of grinding and polishing. For the last five years, we have polished our concrete at World of Concrete using a propane machine and the floor always turns out great!


I have scratches everywhere in my polished concrete. Why?

There are many possible reasons for this to happen. Here are a few possible causes:

scratched concrete1: Poor Execution of the Work

In many cases the operators of the machines have either gone too fast for the tools to properly process the surface of the concrete; or, in other cases, they may have completely missed spots of the floor during different phases of the polishing process. Work discipline during concrete polishing is of huge importance because for the surface of the polished to look consistent and scratch free, the whole surface must be processed equally by each grit of the process.

Another common error during execution is not cleaning the floor between the polishing steps (vacuuming or wet scrubbing) and not keeping the area closed to other traffic. Forgetting either of these requirements can lead to the same condition – contamination!