What Is Concrete Surface Profile (CSP)? What Grinding Standard Should a Floor Meet?

When a contractor says a floor has been ground to CSP 3 or CSP 5, many project owners do not know what that number means or how to check it. CSP is the way to name the degree of roughness of a concrete surface after treatment, and it directly decides whether a coating will bond firmly or not. This article explains what CSP is, how the different roughness levels differ, and what grinding standard a floor should meet for each type of coating system.

The overview of concrete floor preparation before epoxy coating already mentioned floor grinding as one step; this article looks in depth at the criterion for assessing the surface after grinding alone.

What CSP is

CSP stands for Concrete Surface Profile — the profile of a concrete surface — on the rating scale of the International Concrete Repair Institute (ICRI). The scale comprises levels from CSP 1 to CSP 10, describing surfaces from almost as-cast, only slightly rough, to surfaces deeply cut, exposing large aggregate. Each level is associated with a corresponding surface treatment method and has a visual comparison sample for reference on site.

The important point: CSP describes roughness, not the cleanliness or the hardness of the floor. A surface at the correct CSP but still covered with grinding dust, oil and grease, or a weak cement layer will still give poor coating adhesion. CSP must therefore always go together with surface cleaning and substrate moisture testing.

CSP levels and the methods that create them

• CSP 1 to CSP 2: a surface that is almost flat, only slightly rough. Usually created by light grinding or scrubbing. Suitable for thin coatings, where the floor is in good condition.
• CSP 3 to CSP 5: a clearly rough surface, beginning to expose fine aggregate. Usually created by diamond grinding or light shot blasting. This is the range most commonly encountered for roller-applied systems and thin self-leveling systems.
• CSP 6 to CSP 10: a deeply rough surface, exposing large aggregate, created by heavy shot blasting, scarifying, or chipping. Suitable for thick coatings, repair mortars, or systems needing very high mechanical bond, but at the same time consuming more material because the coating must fill the deep cavities.

The general rule: the thicker the coating and the heavier the load it carries, the higher the CSP needed, because the mechanical bond must be deep enough to hold the coating. Conversely, grinding too deep for a thin coating only wastes material and creates an uneven surface that is hard to coat uniformly.

Surface preparation methods

Diamond grinding

A diamond-disc grinder gives uniform roughness, controllable depth, and little dust if dust extraction is fitted. This is the most common method in factories that remain partly in operation, because it causes little vibration and little impact on the structure. Its limitations are slow speed over large areas and difficulty in corners and at wall bases.

Steel shot blasting

Shot blasting creates uniform roughness over a wide area and cleans the surface well, suiting large factory floors that need a medium to high CSP. This method requires specialised equipment and shot recovery, and it can create a surface that varies slightly between machine passes if operation is uneven.

Scarifying and chipping

Scarifying and chipping are used when a thick old coating, damaged concrete, or a very high CSP must be removed. Their drawbacks are vibration and noise, and they can create micro-cracks if applied too aggressively on a weak floor. After scarifying or chipping, the floor usually needs to be ground again to flatten sharp ridges before coating.

Acid etching

Acid etching was once widely used because it is cheap, but it is now rarely recommended for epoxy systems requiring high adhesion: acid is hard to control for uniformity, can leave salts in the concrete pores, and can cause adhesion problems later if neutralisation and rinsing are not thorough. For industrial floors, mechanical grinding or shot blasting is the safer choice.

Checking the surface after treatment

Checking CSP on site is mainly done by visual comparison with a standard sample and by feeling the roughness by hand, combined with a cleanliness check: the surface must be free of dust, oil, weak cement layers, and contaminants. Locations most often missed are wall corners, column bases, expansion joint edges, and areas under equipment that has been moved away. Another check point that is often forgotten is surface hardness: a floor that is too weak and friable can peel together with the surface concrete layer even if it meets the CSP requirement.

Before coating, the application team should agree in writing on the CSP required for each area, the treatment method, and the checking method. A verbal agreement on vague phrases such as a clean grind or a thorough grind is a common source of acceptance disputes, because the two sides understand two different roughness levels.

For a self-leveling system such as LevelFlow, the surface profile requirement needs to be confirmed all the more clearly, because a thick self-leveling layer will fill a deep profile and consume much more material if the floor is ground deeper than designed. Conversely, a floor that is too flat will leave the self-leveling layer short of mechanical bond.

Note: this article presents the general framework of epoxy coating materials, not Kadier-specific specifications. The specific parameters of each coating system are valid only as stated in the official technical data sheet of that product.

Request a consultation on the coating system suited to your floor condition.

Illustration: Pexels / Ksenia Chernaya.