Mechanical forms of concrete preparation, such as grinding or shot blasting, are the most effective ways to prepare a concrete surface for epoxy and resinous coatings. Epoxy coating and resinous flooring manufacturers only approve of these two methods for floor preparation.
Ensuring proper bonding to the concrete surface with the right profile will drastically improve the lifespan and performance of an epoxy flooring system. Done properly, shot blasting or grinding will remove any dirt, dust, previous coatings, sealers, stains, or other foreign material for a clean and well-prepared surface. The number one cause of epoxy floor failure is improper floor preparation, and it is more common than you think.
Selecting which mechanical method for concrete surface preparation largely depends on the type of system that will be installed. Shot blasting is the preferred method for thick-mil epoxy coatings. For thinner-mil coatings, grinding may be best.
What are the pros of concrete grinding?
Grinding equipment comes in many different sizes and weights and can work in tight areas, corners, and along edges, and all have dust-free capability
Grinders can accept a variety of diamond tooling that will remove a multitude of existing concrete substrate conditions, such as heavy coatings or adhesives
Grinding is recommended for all coating systems, especially thin-mil. systems, and always for clear concrete sealers
What are the cons of concrete grinding?
Grinding is a slower process than shot blasting and is less cost-effective
Grinding can be very labor-intensive, sometimes requiring a lot of work on hands and knees throughout the process
Grinding is limited to smoother concrete surface profiles (CSP)
What are the pros of shot blasting?
Shot blasting is environmentally friendly and, like grinding, can be a dust-free solution with proper filtration
Shot blasting is faster and more cost-effective than grinding
Shot blasting can provide increased bonding with its ability to achieve rougher CSP levels
Most epoxy systems only recommend shot blasting
What are the cons of shot blasting?
Shot blasting equipment may have difficulty reaching tight spaces, edges, or corners, and grinders may be required to complete the preparation process
Shot blasting provides limited surface leveling.
Shot blasting is noisy, causes vibration, and requires heavy electrical power
Shot blasting can cause minor surface damage, such as pits and indentations in weak or deteriorated concrete.
Shot blasting will not remove heavy coatings, adhesive residue, or other tacky adhesives
Shot blasting is not recommended for the application of thin layered coatings or decorative coatings and should never be used for clear concrete sealers. The blast “track” marks, sometimes called cornrows, will often transfer through the finished product.
Providing an attractive, durable, and long-lasting epoxy floor installation requires proper mechanical preparation as its foundation for success. For more information on epoxy flooring, resinous coatings, and concrete surface preparation, please contact SRI & Co. at 973-832-7627.
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