Reasons your epoxy flooring installation has gone wrong (and how to avoid it)

As one of the country’s leading epoxy flooring suppliers, we want to see our clients satisfied with their flooring solutions for years to come.

Regrettably, improper application can occasionally cause epoxy floor coatings to fail. Fortunately, there are a few simple solutions to installers’ issues, many of which can be easily avoided.

Questionable substrate integrity

The quality of the concrete substrate is critical for the success of your epoxy flooring system. If the concrete is weak underneath, you can be assured that the product will fail in time. This is because epoxy resins exhibit high bond strengths once fully cured. If the cohesive strength of the concrete is insufficient to match the bond strength of the epoxy, the epoxy will begin to either crack or delaminate, taking some of the concrete surface with it. The result will be cracked or broken concrete and generally a mess. 

It is recommended that the concrete compressive strength be at least 20 MPa with a cohesive strength of no less than 1.5 MPa. Unfortunately, there is a lot of poor concrete on many sites in South Africa, so it is advisable to bring a Schmidt hammer to the site to test before starting your flooring application process.

Poor surface preparation

The surface to which you are applying the epoxy flooring solution should be properly prepared before starting. This means ensuring that the surface is clean and dry and that no debris is visible on the floor. 

We recommend using a shot blast or diamond grinder to prepare the surface to an open pore texture and ensure a clean profile of 80 to 100-grit sandpaper texture with visible aggregates, guaranteeing the proper adhesion and penetration of the primer resins into the concrete substrate.

Using the incorrect primer or no primer at all

Primer is non-negotiable when it comes to epoxy floors, especially for high-build and self-levelling industrial-grade epoxy flooring. While some manufacturers may not say a primer is necessary, it is a critical part of the preparation process and should not be left out.

A primer will ensure the concrete is adequately sealed and that any further topcoats will adhere properly. The low viscosity of primers ensures that they penetrate into the pores and improve the integrity of the top layer of the substrate. It also plays a key role in ensuring that outgassing does not occur, which can ruin your top coat by causing bubbles and fisheyes to form.

Too much moisture

Before applying your epoxy flooring solution, you must ensure that the surface has no moisture content, ideally below 6%, and that the humidity in the space is not higher than 75%. Water can cause significant detriment to the epoxy resin system, causing blushing, poor adhesion, blistering and other potential issues. 

Before installing the floor, make sure to use moisture mitigation measures if the substrate appears to have darkened and there is a noticeable smell of dampness in the air. Before installing the floor, a moisture meter reading must be taken. Grinding the floor can also assist in removing unwanted moisture by opening up pores and ensuring that the substrate can dry out.

Incorrect mixing

Mixing epoxy resins with their respective activators/hardeners is a critical part of the process. The chemical reaction that occurs when these components are mixed ensures that the floor will cure correctly and ensure the full performance of the floor is reached. 

However, improper mixing of these ingredients can result in a flooring solution that has not properly cured. The mixing should be done by a slow-speed but high-torque mixing device designed for the purpose. Using a stick to stir the mixture, shaking the mixture in a bucket, or using a household drill are not adequate ways of mixing the resins efficiently to ensure both resin and activator make good contact with one another.

Mixing too vigorously can cause entrapped air while using a stick will result in an uneven mixture and an improper thorough cure. Epoxy should be mixed slowly for several minutes with the sides and bottom continuously scraped, and mixing should be repeated using two mixing vessels. Once thoroughly mixed, the product should then be poured into place immediately without further delay, as certain products have shorter or longer working times.

Partial curing

All epoxy systems consist of two or more components which only work properly when mixed in the correct ratio and with the correct mixing tool. Partial curing occurs when mixing methods are not adhered to. Generally speaking, an epoxy flooring solution should harden to its maximum hardness at about 36 hours. If it is still not hard at this point, then it is likely that your mixing process was unsuccessful. Another problem that can occur is that the wrong components from different products are mixed together. For example, the activator portion of one system is not designed to do the same job for another system. So, ensure you have read the labels correctly and that the correct Part A is partnered with the correct Part B. 

Fish eyes or visual defects occurring

Fish eyes are a visual circular-shaped anomaly generally caused by an incompatibility due to a contaminant such as oil or silicone. Additionally, surface tension effects or poor substrate wetting may result in fish eyes. Another possible cause may be when certain epoxy types are spread at the incorrect specified thickness, either too thin or too thick. It is important to ensure the primer surface is clean and contaminant-free. Some of these imperfections will cause premature failure of the floor later on and become costly to fix. Thankfully, they can be prevented by carefully following all the manufacturer’s application instructions and checking the surface after each step of the way or contacting the manufacturer for advice. The best way to avoid fish eyes is to properly prepare the surface, remove all possible contaminants and adhere to the manufacturer’s specifications for the recommended thickness of the application.

Inappropriate temperature

The temperatures on the site need to be at an appropriate level to ensure that curing and installation go smoothly. We recommend that both the substrate and the ambient air on-site temperatures be between 20 and 25 °C when mixing and installing epoxy flooring. Products need to be on-site 36 hours before installation to allow for acclimatisation. 

Using the wrong application tools

Applying an epoxy flooring solution requires the use of the appropriate tools. Different tools can be used to get the job done. Therefore, we recommend that you check with the manufacturer to ensure that the correct tools are used for the flooring solution you are applying. Some applications require using a brush or mohair roller, while others require a trowel, notched rakes and spike rollers.

Ensure that you follow the application instructions to achieve the best results.

Here at Technical Finishes, we pride ourselves on being one of the most reputable epoxy suppliers in South Africa. Contact us today to get a flooring solution that you can rely on!

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