By When most people think of epoxy flooring, they picture the finished product—glossy, seamless, and durable. But what often goes unnoticed is the most critical phase of the job: surface preparation. For professional epoxy contractors, the quality and longevity of any flooring project hinge on what happens before the epoxy is poured.
Why Subfloor Prep Matters
Epoxy may be tough, but it’s only as good as the surface it adheres to. Improperly prepared concrete can lead to adhesion failures, bubbles, peeling, or uneven finishes. That’s why experienced contractors dedicate significant time to prepping subfloors before the resin ever touches the ground.
Step 1: Moisture Testing
Before anything else, contractors test for moisture content in the concrete. Excessive moisture vapor from the slab can compromise epoxy adhesion, leading to delamination over time. Moisture barriers or primers are used if necessary to mitigate the risk.
Step 2: Crack and Damage Repairs
Cracks, spalling, and pitted areas need to be patched and leveled. Epoxy fillers or cementitious repair products are often used. Leaving damage untreated leads to unsightly results and weak spots.
Step 3: Surface Profiling
This step creates the texture epoxy needs to bond properly. Contractors may use:
- Diamond grinding – common for smoothing and opening up the concrete surface.
- Shot blasting – ideal for heavy-duty jobs or removing stubborn coatings.
- Scarifying – used when deep layers need to be removed.
Each method is chosen based on the condition of the floor and the type of epoxy system being installed.
Step 4: Thorough Cleaning
After profiling, all dust, grease, and residues must be completely removed. HEPA-filter vacuums and degreasers are standard tools. Cleanliness directly affects adhesion and finish clarity.
Step 5: Priming for Success
A primer coat isn’t always necessary, but for challenging or porous surfaces, it can ensure stronger bonding and a more even application.
Final Thoughts
Subfloor preparation may be the “dirty work” of epoxy installation, but it’s what separates a short-lived floor from a decades-long investment. Homeowners and business owners alike should always ask their contractors about their prep process before signing on the dotted line.
Need help with an epoxy project? Make sure your contractor treats preparation with the same care as application—it’s the foundation of a flawless floor.
