Epoxy Floor Acceptance: Which Criteria?

Acceptance inspection is the step that confirms whether an installed epoxy floor meets what the two parties agreed, before it is put into use. Many disputes about epoxy floors do not arise from installation technique but from the fact that, from the outset, nobody wrote down the acceptance criteria: what to check, how to check it, and what level counts as passing.

This article presents a framework of acceptance criteria based on the general properties of epoxy floor coating material, referring to the standard frameworks TCVN 9014:2011 and TCVN 12574-2018. This is a general framework for the parties to agree on, not the specific parameters of a particular coating system. The specific parameters of each Kadier system are not published in this article; when official technical data sheets (TDS) become available, the content will be updated accordingly.

First principle: agree first, measure later

A good acceptance record is prepared before installation, not written in a hurry on handover day. The parties should agree in writing: the scope of acceptance (the whole floor or individual areas), the coating system installed (roller-applied or self-leveling), the design thickness, the colour, any special areas (forklift aisles, areas exposed to chemicals, wall bases), and how defects found are to be handled.

This matters because many criteria are a matter of perception if there is no reference standard to compare against. For example, “even colour” needs an approved colour sample or colour code to compare with; “flat surface” needs an agreed measurement method, rather than judgement by eye under a single lighting condition.

Criterion group 1: surface observation

Observation is the first step and usually reveals the most defects. When inspecting, walk the entire floor surface under normal working light, and also shine light at an angle over areas of doubt so defects show clearly.

• Colour and gloss: colour even within each area, with no obvious patchiness and no marked deviation from the approved sample.
• Seamless surface: no cracks, no peeling, no bubbling, and no clearly visible roller or brush marks left as streaks.
• Surface cleanliness: no dust, sand or foreign matter embedded in the coating; edges, corners and wall bases neatly finished.
• Line marking and zoning (if any): lines straight, clear, and in the agreed positions and colours.

Surface defects should be recorded with their specific locations on a floor plan, with photographs, instead of a vague note such as “the floor is not yet good-looking”. Recording the exact location helps the installation team fix the right spot and makes re-inspection faster.

Criterion group 2: thickness, flatness and adhesion

These three indicators directly reflect the quality of the coating system and its future load-bearing capacity.

• Coating thickness: measured at many representative points in each area, especially on main aisles and load-bearing areas. The actual thickness should stay close to the agreed design thickness; the general thickness range for epoxy floors is usually 0.2–3 mm depending on the system and function, but the figure applied to each project must follow the design and the technical data sheet of that system.
• Flatness: checked with a straightedge or an agreed method, focusing on areas where forklifts travel and where machinery is placed, because an uneven floor affects operation and safety.
• Adhesion: the pull-off test is the commonly used method for assessing whether the coating bonds firmly to the concrete substrate. Whether this test is carried out, at how many points, and how the results are assessed should be agreed in advance, because adhesion testing is locally destructive and the tested spots need to be repaired afterwards.

Before measuring thickness or adhesion, one foundational step should be noted, as presented in the article concrete floor preparation before epoxy coating: a weak substrate, high moisture or a substrate not properly ground and crack-repaired can all cause the coating to peel later, even if the surface still looks good at handover.

Criterion group 3: fitness for use

A floor that looks good but is slippery when wet, or wears quickly in forklift aisles, still does not meet the requirements for use. Depending on function, the parties should also check:

• Anti-slip: especially on walkways, wet areas, slopes and areas with oil or grease. The anti-slip requirement should match the actual conditions of use, not only be checked when the floor is dry.
• Chemical resistance and abrasion resistance: checked against the types of chemicals and the actual contact frequency of the project, based on the technical data sheet of the chosen system.
• Ease of cleaning: a seamless surface with no joints is a general advantage of epoxy floors; at acceptance, a sample area should be cleaned using the method the plant will use every day.
• Time before use: acceptance and handover should take place only once the coating has cured sufficiently according to the system manufacturer’s instructions; putting heavy loads on the floor too early can damage the coating even if installation was correct.

What should an acceptance record contain?

A complete acceptance record usually includes: project information and the scope of acceptance; the coating system and design thickness; the list of criteria checked and the result for each criterion; a list of defects with locations, photographs and rectification deadlines; the acceptance conclusion (accepted, accepted conditionally subject to defect rectification, or not accepted); and the signatures of the parties.

For minor, localised defects, the parties may agree on conditional acceptance with a clear repair schedule. For defects affecting the structure of the coating layer, such as widespread peeling or poor adhesion, thorough repair and re-inspection of that area are needed, instead of merely applying another thin coat on top to hide the defect.

The process from survey, substrate preparation and installation through to handover is presented as a whole in the article standard epoxy flooring installation process, from survey to handover. Acceptance inspection is the final step of that process, but its criteria should be settled right from the start, so that both the project owner and the contractor measure by the same yardstick.

Which system for a project about to be accepted?

Acceptance criteria are always tied to the chosen system: a multi-layer roller-applied system such as RollCoat and a self-leveling system such as LevelFlow have different design thicknesses and surface requirements, so the same detailed criteria table cannot be used for both. When seeking advice, the project owner should ask the supplier to state clearly the design thickness, the inspection methods and the technical data sheet accompanying the exact system to be installed.

Get advice on the acceptance criteria suited to your project, together with the technical data sheet of the corresponding system when available.

Illustration: Pexels — Tiger Lily. Image source: pexels.com.