Prep is where epoxy floors succeed or fail
Ask anyone who installs floors for a living and they will tell you the same thing: the coating is only as good as the preparation underneath it. Nearly every epoxy failure — peeling, bubbling, delamination — traces back to prep that was rushed or skipped. Get the concrete ready properly and a good coating will last well over a decade. Skip it, and even the best product will let go.
This guide walks through how a concrete floor is correctly prepared for epoxy, and why each step matters.
Step 1: Assess and test the slab
Before any grinding, the slab needs to be understood:
- Age and condition — cracks, spalling, pitting, and previous coatings
- Contamination — oil, grease, and chemical staining that must be removed
- Moisture — the single most overlooked risk on BC slabs
- Existing coatings — whether they must come off entirely
Moisture testing is critical. Slabs on grade in the Lower Mainland and Fraser Valley can push significant water vapour up through the concrete. If moisture is high and untreated, that vapour pressure will lift the epoxy off the floor. Testing tells us whether a moisture-mitigation primer is required before anything else. This is a core part of industrial epoxy and urethane work.
Step 2: Clean and decontaminate
The surface must be free of anything that blocks adhesion:
- Remove all loose debris, dust, and old flaking coatings
- Degrease oil- and grease-contaminated areas thoroughly
- Address any chemical or biological contamination
Oil is the enemy of adhesion. Contaminated concrete may need repeated degreasing before it will accept a coating.
Step 3: Mechanically profile the concrete
This is the heart of proper prep. Epoxy needs a profiled surface — slightly rough, open, and porous — to bond mechanically. A smooth, sealed, or troweled slab will not hold a coating no matter how good the product. Two methods dominate:
- Diamond grinding. Rotating diamond discs abrade the surface, remove old coatings and laitance, and open the concrete's pores. This is the standard for most commercial and garage floors and is the foundation of quality concrete polishing and repair.
- Shot blasting. Steel shot is fired at the floor to aggressively profile large industrial areas quickly. Ideal for big warehouses and high-build systems.
Acid etching is not a substitute. It is inconsistent, does not remove coatings, and is unreliable — professional installs use mechanical prep. The goal is a uniform, measurable profile (often described by CSP, the Concrete Surface Profile scale) matched to the coating being applied.
Step 4: Repair cracks, joints, and defects
Once the floor is profiled, defects are addressed:
- Cracks are chased out and filled with an appropriate repair resin
- Spalls and pits are patched and levelled
- Control and expansion joints are treated according to the system — some are filled, some are honoured through the coating
- Low spots are levelled so the finished floor drains and looks right
Skipping repairs means every flaw telegraphs through the finished coating.
Step 5: Apply moisture mitigation (if needed)
If testing flagged elevated moisture, a moisture-mitigation primer goes down before the epoxy. This creates a barrier that manages vapour pressure and protects the coating from being pushed off the slab. On many BC ground-level slabs this step is the difference between a floor that lasts and one that fails within a year.
Step 6: Prime, then coat
With a clean, profiled, repaired, and dry surface, the system is built up:
- A primer penetrates and locks into the profiled concrete
- Base and build coats provide thickness and colour
- Flake or decorative media is broadcast if specified
- A topcoat — epoxy, urethane, or polyaspartic — provides wear, chemical, and UV resistance
Each layer needs the correct cure time and conditions before the next goes on. Rushing recoat windows is another common cause of failure.
Why cutting corners on prep costs more
A bargain quote that skips grinding, moisture testing, or repairs is not a saving — it is a deferred bill. A coating that delaminates has to be removed and redone from scratch, meaning you pay twice plus the downtime. Proper prep is the majority of the labour precisely because it is the majority of the value.
We prep floors to last
Every floor we install starts with a full assessment, moisture testing, and mechanical profiling — and it is backed by a written workmanship warranty. If you want an epoxy or garage and epoxy floor system that lasts, the prep is where that promise is kept.
We serve Surrey, Coquitlam, and the wider Lower Mainland and Fraser Valley with free on-site assessments including moisture testing.
Call 778-538-1802 or email operations@precisionindustrialpainting.com to book yours.