Concrete Scarifier vs. Grinder vs Shotblaster: Essential Tools for Surface Preparation

When preparing a concrete surface for the installation of a flooring system, whether it be a coating (thin) or topping (thick), you will use a mechanical means of prep. Mechanical prep is using a mechanical device to clean and roughen the surface removing all bond-inhibiting materials.

Three main pieces of surface preparation equipment should be in every contractor’s trailer, concrete scarifier, grinder, and shotblaster. Each one is a specialist. Can one of these do everything, no they cannot. That is why each one of them will increase your production on one job or another.

Key Differences and Applications

A concrete scarifier (planer or milling machine) is a drum-type machine. The drum spins at a high rate of speed on a horizontal plane. On the drum are shafts that hold the cutting wheels or flails. The aggressiveness of flails used is based on what your intentions are. The depth and roughness of the cut will direct you to the proper set.

The concrete scarifier is best at removing stock. When there is curling at a joint and the goal is to have both shoulders of the joint on a level plane, a scarifier will do the job. If there is a high spot that needs to be removed, a scarifier will be the machine of choice. Depending on the flooring system, a scarifier might also provide the ultimate surface profile.

When a thin mil flooring system is being applied, a concrete grinder will be an excellent choice. Grinders are fitted with diamond tooling. There are types of tools based on what you are trying to do. There are diamond tools designed to remove carpet adhesive, and previously applied resinous coating, and to mechanically clean the surface leaving a semi-smooth or rough, open profile. It is very versatile and should be the first piece of prep equipment that you own.

Shotblasting is quite an uncomplicated process. It throws steel shot (BB’s) to the ground etching the surface while moving across the floor. The size of the shot and the travel speed of the machine dictate the level of etch it produces. It is not designed to produce a smooth floor nor remove an adhesive or coating like a grinder or remove ¼” of concrete like a scarifier. It produces a great surface profile to accept a coating.

Niagara Machine specializes in concrete surface preparation equipment. If you would like to buy one or all three machines, they can get you to the right one for your needs.

Choosing the Right Tool

Selecting the proper machine will depend on the substrate and the system going down. There might be times when two of these will be used on the same project. If you need to remove a coating a grinder will work best. If you have a shot blaster to do a final cleanup and a medium build material is being applied, this process will perform very well.

If you have lippage to remove, a scarifier is the machine. After it has leveled the lip, a grinder can be used to smooth things out if a thin system will be applied. If the system requires a Concrete Surface Profile (CSP) of 5 or greater, the scarifier can be used alone. If you only have a grinder, you fit it with Bush Hammers to produce a similar profile.

Common Surface Preparation Mistakes

It is almost impossible to make a mistake in selecting the proper prep machine if you know what the flooring system requires and what the machine will produce. Tie them together and you will produce a prepared floor that is exactly what the doctor ordered.

There might be a time when abrading the surface is just not enough. When oil or another liquid has penetrated the substrate deeper than what the surface prep method will take care of, there are poultice materials that when allowed to sit on the contaminate will draw it from the concrete. Microbes can also be used. These “bugs” eat the oil. The substrate will remain stained, but the actual oil will be removed.

Conclusion

Surface preparation is a major step in every flooring project. Whether installing a wood floor or a resinous system on concrete, the substrate will have an impact on the final appearance and performance. Selecting the right equipment to perform the work will not only reduce the time spent but also obtain the recommended surface profile.

Concrete scarifiers, grinders, and shot blasters all can abrade a concrete surface. Each one has its specialty in the amount of concrete it will remove, the surface profile it produces, and how fast it will perform the work. Understanding this will help guide you in selecting the proper one.

Surface prep can be overwhelming at times. You can run into something you have not dealt with in the past. Contacting a surface preparation professional is a safe way to start the process. Niagara Machine has field representatives to help you with this. They have been trained and field-assessed in all forms of surface preparation. Even old dogs can learn new tricks.