After shot blasting, epoxy flooring can be applied directly, provided the surface preparation meets the required standards.
Shot blasting is the most crucial step before epoxy flooring application. Its purpose is to thoroughly remove old coatings, laitance, oil stains, and other contaminants by impacting the surface with high-speed steel shot, creating a uniformly rough "pitted" surface on the concrete. This significantly improves the adhesion between the epoxy coating and the substrate.
After shot blasting, the following points must be checked before proceeding with epoxy flooring application:
Surface cleanliness: A high-powered vacuum cleaner must be used to completely remove all dust generated during shot blasting, ensuring no residual particles or loose dust remain.
Moisture content: The moisture content of the concrete substrate should be below 6%~8%, otherwise, subsequent coating blistering and delamination may occur.
Smoothness and defects: Cracks, pits, and other defects must be repaired with epoxy mortar and ground smooth before application.
Free from oil and moisture: If oil stains penetrate the substrate, clean with an industrial degreaser or treat with heat; there should be no standing water in low-lying areas.
If all the above conditions are met, proceed with the standard process of applying epoxy primer → intermediate coat → topcoat. The following are five key acceptance standards before epoxy flooring construction to ensure the substrate meets the standards and effectively avoid rework and quality issues:
Substrate strength: Concrete compressive strength must be ≥C25, rebound strength not less than 80% of design strength, and the surface must be free of sand, powder, or hollow areas.
Moisture content control: The moisture content of the substrate should be ≤8%, especially for first floors or basements, which must have undergone moisture-proofing treatment to prevent blistering and peeling of the coating later.
Smoothness requirements: Use a 2-meter straightedge for inspection; gaps should be ≤3mm. Excessive local height differences require prior repair and sanding to ensure uniform coating thickness.
Surface Cleanliness: After shot blasting or grinding, dust, oil, laitance, and other impurities must be thoroughly removed. Industrial vacuum cleaners are recommended to ensure proper adhesion.
Environmental Conditions: The ambient temperature should be between 10–35℃, relative humidity ≤85%, and there should be no standing water or dust to ensure proper coating curing.
These standards are fundamental to successful epoxy flooring construction. Failure to meet any of these standards may affect the final performance and service life.
