By Daniel Green
Epoxy flooring is a chemical resistant, hard-wearing resurfacer and/or decorative finish applied to concrete and other hardened surfaces. Its name derives from the two-part system of products that when mixed, sets off a timed catalyst that ends up curing. It is not paint. It is usually applied in industrial scenarios where hardy floor coverings are required.
The coating can be applied in full coverage across the entire floor; or in partial coverage such as non-slip zones and delineation markings. In the case of slippage it can have an aggregate applied to it for traction. There are even elite industrial grade epoxies that chemically combine with the slab for deeper adhesion. All epoxy coatings can be tinted with virtually any colour there is.
The most common scenarios are warehouses, cool rooms & freezers, medical & food grade facilities and mechanical workshops. Other popular environments are ship decks, offshore oil rigs, air and seaports and shopping malls. It is suitable for walls, floors, vessels and more. In short – anywhere an extremely durable surface is required.
But for the most part epoxy flooring is applied to concrete. We will focus there.
There is a range of grinders, each with their strengths and weaknesses and each with their most favourable working conditions. But whatever the machine, all utilise removable abrasive shoes of differing coarseness and cutting power. Diamond is considered the best abrading material for cutting through epoxies, adhesives and concrete.
Hand grinders. On the smaller end of the scale are hand grinders. These are the size of a regular 5” grinder, the kind you would use to cut or grind metal. They fit in the palm of your hand and can be easily manipulated for detail work. Like a 5”, the discs are interchangeable and come in varying grades of aggression.
Floor grinders. In the middle is the floor grinder. It’s the same size as the floor polishers used to clean shopping malls and hospitals. On one end are handles to control the machine and on the other are the shoes attached to a spinning disc.
Remote controlled grinders. At the large end is the remote-controlled floor grinder. It sweeps a larger surface area again and comes with its own built-in dust-collection system.
Because floor grinding is essentially reducing epoxy, vinyl glue and concrete to dust, several layers of operator protection are required. On top of the usual construction PPE a proper respirator must be worn. This excessive dust means a special vacuum cleaner is needed.
THE REMOVAL PROCESS
All things wear out, tastes included, so at some stage your epoxy floor coating will need attention and/or removal. Because it is inherently durable it can be quite difficult to remove, with mechanical means being the most favourable approach. Acetone and heat can be used but this is usually reserved for coatings that are designed for domestic applications. Anything hardier will require grinding. Whilst grinding is best practice, within that are further considerations: the final finish, age & hardness of the concrete and intended use of the space.
Preparation. The first step is to remove any floor coverings such as carpet, tiles or vinyl. The carpet should come up easily, as should the underlay. Any adhesive can remain behind. If the floor was tiled, then both the tiles and bedding need to be removed back to a bare slab. If it was vinyl then, like carpet, the adhesive can stay.
Test patch. Prior to beginning any lengthy runs across the surface, use a hand grinder to do a test patch somewhere less conspicuous. This will determine how resistant the epoxy or adhesive is, as well as how favourable or unfavourable the underlying concrete will be. Both of these variables will determine your choice of grinding shoes.
Raised surfaces. If the floor contains any tactile material, remove this first. Examples are: non-slip strips on floors or on steps, and partial coverings like line markings. These surfaces must be brought back to the same height as the remainder of the floor. You cannot use a grinder that has more surface area than the epoxy it is removing or you risk gouging the surrounding area.
Shoes. Shoe selection is as important as any other factor in the process. Shoes too light will become glazed, too heavy and they will leave scratches. Perfect recommends using 20 grit shoes for the first pass of an average layer of full coverage epoxy.
Removal. Using a floor grinder, walk the machine across the entire floor in a series of parallel runs. This process will need your full attention at all times. Too fast and you won’t remove enough material, too slow and you risk cutting too deeply. Too much overlap will leave an uneven surface, not enough and you will miss areas, meaning another pass.
Dust. If you’re not using a sealed unit that collects its own dust, then you will need to clean up. Hosing is fine as long as the slurry does not impact the environment. Vacuums are better but are a lengthier clean up.
Post grind. There are further treatments that can be applied such as: sealing, exposed aggregate grinding and polishing. Depending on the intended plans for the area, some of these will require different shoes, products and processes.
Unless you do it everyday removal of epoxy flooring can be challenging and it may end up costing more than if you hired a professional. If you’d like sound advice, contact Rodrigo at Perfect Concrete Care: 0481 231 493.