In the past, a “floor coating” was a relatively straightforward generic product that could easily be specified. Today, everything from the thickness of the floor, to the service environment, to its performance characteristics, colour and surface finish properties are to be kept in mind when specifying floor coatings.
Floor coatings, such as epoxy finishes, usually appear on concrete floors where high traffic volume, clean and/or hygienic conditions and where an aesthetic appearance is necessary. Some of the common applications include vehicle showrooms, pharmaceutical laboratories, food and beverage processing plants, general purpose warehouses, hospitals and more.
Floor coatings are far more than an aesthetic solution. When applied over a sound and well prepared substrate, the epoxy components when blended chemically react to create a product with strength and durability and aesthetic properties that are hard to match. Standard concrete generally has a compressive strength of only 25 MPa also requiring a minimum of 1.5 MPa tensile adhesion strength, which in most cases will not be sufficient to serve the environment that it will be subjected to, typically damage from tools, equipment, shopping trolleys, forklifts, chemical resistance and aesthetics as an example. If you want your floor to provide longevity, then it’s worthwhile investing in an epoxy flooring system.
As with many flooring systems, it is much easier and more cost-effective to get the initial installation right than to try to “epoxy over epoxy” and repair a less-than-stellar job.
It is for this reason that FLOORS in Africa sought input from floor coating manufacturers to find out what some of their top tips are for specifying coatings. Here is what they say:
1. Evaluate the surface
The surface must be suitable to accept the chosen floor coating, must be structurally sound, clean and free of any surface contamination. Check for cracks, density and porosity before installation. It is imperative that the surface be free of any moisture, or the effects of hydrostatic or osmotic pressure. A DPC on the subgrade below the concrete plays a vital role in preventing rising moisture/damp.
2. Floor preparation
A floor is only as good as its sub-base, so preparation before applying any coating is very important. If a floor that is to receive a resin coating finish is not smooth and well prepared, all the imperfections will show through once the coating has been applied. It is of extreme importance to study the floor surface preparation required for each type of product considered.
3. Application and environment
It is very important to take into account the usage of the floor before specifying a suitable epoxy system. If there is only going to be pedestrian traffic, a thin film coating will be sufficient. However, if there is going to be heavy duty forklift and other mechanical traffic, a thicker, more durable coating or screed will need to be specified. The correct system and thickness is essential for longevity.
Some of the operational criteria and maintenance requirements that need to be considered when selecting a flooring system that may include hygiene like FDA approval etc., slip resistance, chemical exposure, thermal shock and cycling (where the ambient temperature of the environment changes significantly), as well as cleaning and maintenance.
4. Maintenance plan
Specifying bodies also need to take into account that the contractor and client include a suitable maintenance plan where required for the flooring system, available from the manufacturer.
5. Suitable applicators
It is critical that a competent contractor is appointed to do the application. Not only do professional applicators have the correct equipment, they are also able to ensure that the required finish is achieved, as specified.
6. Client expectations
It is important that the client understands the aesthetics and performance requirements of the product as well as the cleaning and maintenance of the finished application. More importantly the applicator must apply sample as a reference and standard to be accepted by the client.
What can go wrong?
An epoxy or resin floor can last for decades if it is specified and installed correctly. If this doesn’t happen, however, one or more of the following problems may arise:
• Bubbling in floor coatings
This is the most common problem with epoxy floors. The bubbles in cured epoxy floors are generally very small (the size of the pinhead) and may appear randomly or in clusters. These bubbles can be caused by outgassing of the concrete substrate, or when the product isn’t mixed correctly or too fast, leading to air entrapment. Other sources of the problem can be excessive mixing such as using a power drill at high speed, or when there is excessive temperature causing pressure differentials leads to trapped air that wants to equalise. Slowly circulate the mixture in a large container and be sure to get the correct ratio when the resin and hardener are mixed.
• Craters and bubbles
A bubble in an epoxy floor contains air or moisture, whereas a crater leaves an indentation in the surface that is generally caused through dirt or contamination while the epoxy is still curing.
• A dull and uneven appearance
If the epoxy coat is applied in too hot or too cold climatic conditions, or when airflow blows over a curing surface, a dull and uneven appearance can be the result. Epoxy is very sensitive to temperature fluctuations and needs to be applied according to the manufacturer’s guidelines. Also, remove ventilation fans, switch off air-conditioning and close doors and large windows that could lead to wind blowing across the curing surface. If dust is present during curing, it can cause small pinholes, or “fish eyes” in the final surface finish.
Peeling and poor adhesion is usually the result of an inexperienced or careless applicator. It can come from poor surface preparation, contaminated materials not being removed from the surface, an incorrect mixing ratio of the resin and hardener, wide temperature variations, or moisture trapped below the surface.
Specialised tip: Standard concrete generally has a compressive strength of only 25 MPa also requiring a minimum of 1.5 MPa tensile adhesion strength, which in most cases will not be sufficient to serve the environment that it will be subjected to, typically damage from tools, equipment, shopping trolleys, forklifts, chemical resistance and aesthetics as an example. This is why an epoxy flooring system is needed.
Main image courtesy of TAL.
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