Surface Preparation-Why is it Important?

Is surface preparation for a concrete floor necessary prior to applying a topcoat?  Yes, while the priming or prepping method can vary, it serves to smooth the surface by removing built-on particulates. It gives the concrete a brand new look and makes it easier for topcoat particles to bond.  

An uneven surface can mean the difference between a long-lasting surfacing option, and a costly re-do; however, grinding resolves the following: stains, paint, cracks, repaired cracks, and mortar. 

Any professional will also recommend a proper surface coating before applying resins. Not doing so will result in a terrible job. 

Read more about concrete resurfacing in our article ‘Polished Concrete Surfacing- a Definitive Guide’

How does concrete resurfacing work?

Generally, concrete resurfacing requires the removal of a thin layer of concrete to apply an epoxy resin layer. The thick resin is then stamped and rolled into the resulting smooth surface, leaving a shiny, water-proof, and durable concrete-looking surface. 

The ‘Concrete Surface Profile Scale (CSP)’

Certain surfacers require a specific ‘texture’ of concrete for stylistic purposes. As a result, concrete surface preparation professionals have developed the ‘CSP’ scale that ranges from 1-9. The scale measures the smoothness or roughness of a concrete surface, with one being a nearly flat surface to nine being jagged and uneven.

The CSP is used in the latter methods as a form of measurement. However, it is more applicable to diamond grinding due to the amount of control that grinders have. Ontario Specialty Coatings operates on a CSP scale from 2-4 with diamond grinding equipment to achieve an elegant, compact sheen. As professionals in the field, they will only proceed with adding an epoxy topcoat if the proper resurfacing has first been done.

Concrete surface preparation methods

Preparation for concrete resurfacing comes in various methods. However, some are recommended over others due to the amount of control over CSP that they have. 

What is acid washing?

Acid washing is a technique used to strip layers off of surfaces through erosion. As mentioned, debris and films can build up on surfaces; this acid treatment removes the build-up.

The process involves rinsing the area, applying the acid coat, and then rinsing it again while adding neutralizers. The method uses a mixture of water and muriatic acid. Due to the relative unpredictability of the acid, the CSP control is minimal. For finer control, diamond grinding is often preferred. 

Caution should be used if doing this process yourself. We highly recommended having professionals handle muriatic acid due to the dangers associated with its usage. 

Muriatic acid disperses noxious fumes that can irritate both eyes and lungs, so having a mask and goggles is required when working with it. Additionally, neutralizers will need to be present in case the acid becomes too concentrated. 

Environmental harm can occur if the acid seeps into nearby ground. If the acid is not safely pumped away and neutralized, it can kill plants, animals, and humans. 

What is diamond grinding?

Diamond grinding is a method of removing imperfections and old layers of a surface through the use of diamond-toothed belts. Like sandpaper, these belts range from ‘fine’ to ‘coarse’, referring to the size of diamond segments. The more coarse belts grind the initial debris and old surface away. Then the finer belts are moved over the same area multiple times until the desired smoothness is achieved.

This is why diamond grinding is noted to be one of the best preparation methods since the grinding belts can easily control the CSP scale. The resulting smooth layer allows the desired topcoat application to be applied. 

Ontario Specialty Coatings uses diamond grinding for this very reason, which can be detailed in the practice of concrete polishing. Additionally, diamond grinding has the least harmful possible side effects compared to the other options listed here. 

What is abrasive blasting?

Abrasive blasting works in a similar way to diamond grinding but in a much less controlled manner. This process involves shooting sand or other rough particulates at a surface with a powerful machine. The sand particles rip away any leftover paint or other accumulated sediment with this combination of coarseness and air pressure. The CSP control of this method is also unpredictable, just like the acid wash, due to the nature of blowing sand particles. By default, random and excessive scarring will occur. 

Wearing proper safety equipment, goggles, and a respirator is required for this type of work since there are health consequences without them. Inhaling the resulting dust can result in lung diseases such as silicosis. Abrasive sandblasting can be used for surface preparation and cleaning large equipment. 

Sometimes you may notice a crack in your concrete surface. These small cracks can appear as a result of trauma, stress, or merely old age from years of wear and tear. Whether it appeared seemingly out of nowhere or was the result of an isolated incident, there is no need to tear up the entire floor for such a small fix.

Epoxy resins have a more durable molecular composition than concrete, which means that they can fill the missing piece’s role. All that is required is to inject the resin into the area, where it can be left to harden.

The resulting repair will last for years as long as no additional shifts are made in the foundation or excessive stresses.