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Lesson

Choosing the Right Epoxy or Resin System

14 min · Intermediate

The most expensive epoxy in the world will fail on the wrong job, and a budget system will outperform it on the right one. This lesson is about choosing correctly.

The three main families

Epoxy. The workhorse. Excellent chemical resistance, strong adhesion, very hard when cured. The classic choice for industrial, warehouse, garage and commercial floors. The main weakness: pure epoxy yellows and degrades under direct UV, so it’s for indoor or shaded areas.

Polyurethane (PU). More flexible than epoxy, better UV stability and a wider colour range. The usual choice where flexibility (to handle slab movement) or UV resistance matters — external areas, patios, some decorative floors. Slightly lower chemical resistance than epoxy.

Polyaspartic. A faster-curing hybrid. Cures in hours rather than days, with good UV stability and chemical resistance. The go-to when downtime is the constraint — retail, restaurants, facilities that can’t close for a week. Premium price, short pot life, needs an experienced applicator.

Matching to the job

Ask these five questions before you specify:

  1. What’s the traffic? Pedestrian, forklift, heavy industrial — each step up changes the system and the build.
  2. What chemicals will it see? Oils, acids, solvents, cleaning agents — this drives chemical resistance. Epoxy generally wins here.
  3. Is it in UV light? Direct sun → avoid pure epoxy, go PU or polyaspartic.
  4. How much downtime is allowed? Days → epoxy. Hours → polyaspartic.
  5. What’s the budget? Polyaspartic is the premium; epoxy is the value.

Don’t skip the substrate

No coating system is better than its substrate. Before you specify a single litre, confirm:

  • Moisture is within the system’s limit (test it — don’t guess).
  • Profile is adequate (most systems want a profile of 2–3, check with a tape-test).
  • Contamination is gone.

Checklist: Traffic, chemicals, UV, downtime, budget — answer all five, then test the substrate. Only then write the spec.

Key takeaways

  • There is no 'best' epoxy — only the right one for the application.
  • Match the system to chemical exposure, UV exposure and traffic, not just price.
  • Always confirm the substrate moisture and profile before specifying.