1. Preparing a concrete floor for sealing
Before you start, make sure your concrete is cured; in other words, it needs time to dry out. Putting an epoxy sealer on fresh concrete will cause it to bubble later. If it’s an old floor, the first step is to make sure it’s free of contaminants such as old paint or coverings. Then you need to grind it to a relatively smooth finish. To do this you need a concrete grinder and the appropriate diamond cup wheels or disc. These discs contain diamond particles embedded in a metal alloy. The coarseness of the disc is known as its ‘grit’, and the higher the number, the smoother the disc. For concrete polishing you use a number of different discs and polishing pads, but if you’re applying a sealer you may only need two: a 30/40 grit disc (ask the Kennards Hire team which is best for you) and a 60/80 grit disc to smooth it out. It’s important to wear protective clothing when concrete grinding so as not to inhale the dust that is produced. You need a dust mask, safety glasses and ear protection to operate a concrete grinder. Make sure the grinder is attached to a suitably paired dust collector or vacuum cleaner so dust is kept out of the air. The main reason for this is concrete dust is a health hazard. Additionally any dust on the floor will become trapped in the sealer and ruin the result, like a brush bristle in paint.
2. Grinding the Concrete Floor
Fit the coarser of your discs (30/40 grit) to the grinder and turn on the vacuum cleaner. Switch on the machine and begin to grind. When you operate the machine, make sure that you walk in smooth, overlapping lines. Make sure the surface is fully covered. At this stage you are getting rid of any paint, glues, etc, that might have been on the floor. You are also grinding back to a reasonable smoothness. Next, fit the 60/80-grit pads to the machine and repeat the grinding process. The floor will begin to look smooth. After you have been over the floor with the 80-grit discs, vacuum again to remove residual dust. At this stage with concrete polishing there are several more stages to go. But with an epoxy sealer that’s as much grinding as you need to do.
3. Applying the Epoxy Sealer
To do this you need a roller designed for the job, which means a medium-nap, epoxy or polyurethane roller. A cheap paint roller will not do the job as it will shed fibres. Pour a quantity of the sealer into a new paint tray and apply it to the roller. Starting at the furthest corner of the room, begin to work back in straight lines making sure you cover all the surface. Usually you need to apply two coats of sealer, leaving the first to dry overnight before applying the second. Care needs to be taken when drying to prevent dust, insects or the cat getting in and spoiling your hard work. The next day, apply the second coat and again leave overnight before you attempt to walk on it. For the first seven days the sealer is still curing, so try to restrict use to light traffic. An epoxy sealer delivers a polished concrete look without the time and attention to detail involved in polishing. It's durable, protects the floor from stains and gives your floor a classy look. The team at your Kennards Hire branch can answer questions you have about your project and how to prepare your concrete floor for best results.