How to Use a Concrete Grinder to Remove Old Basement Floor Sealant

A concrete grinder is an efficient equipment to remove old basement floor sealant to prepare the surface for tiling, resealing, or simply for polishing. The machine can also remove old paint, rough concrete surfaces, or a stained concrete surface.

Step 1 – Preparation

Rent, borrow, or buy a concrete grinder. Before using the machine, make sure to read the manual thoroughly especially if it is your first time.  Determine how much energy the machine requires. Be sure to know how to attach and detach the grinding pads from the unit as well. Determine how to use the machine to grind the concrete layers evenly. Do not turn on the machine yet unless you already have the most basic technical knowledge on how to operate it.

Step 2 – Clear Out the Concrete Surface

Clear out every object on the basement floor. Remove any debris as well and sweep the floor clean. This will ensure that the grinding pads are not interfered during the grinding operation.

Step 3 – Provide Sufficient Ventilation

Although the equipment is connected to a dust vacuum, there is still a good chance that dust can become airborne. Therefore, wear a respirator and eye goggles, and open all windows and doors to provide good ventilation inside the working area.

Step 4 – Prepare the Grinding Pads

Use a coarse grinding pad for the first grinding pass. The pad is usually 40-grit. However, it is best to read the manual to determine the correct pad to use during coarse grinding. To create a glossy and well polished finish, use a finer grinding pad. Attaching the grinding pads to the unit may require a wrench or a hammer. Check for the manufacturer’s instructions for more details on how to attach the pads correctly.

Step 5 – Coarse-Grinding the Concrete

Attach the coarse grinding pad at the bottom part of the unit and attach the vacuum hose as well.

Determine the starting point and position the unit in that location. Switch the vacuum on and switch the grinder to its grinding mode. Wait for it to rev up to its maximum rotational speed. This happens when it emits a constant pitch. Lower the head of the grinder onto the floor and move the unit in a small circular motion or from side to side. Always move in a straight line. Apply a light pressure to the pad in order for it to grip the floor surface. When the end of the line is reached, switch off the grinder and move it to the next row. Follow the same procedure until the entire sealed layer is removed.

Step 6 – Polishing the Rough Concrete

Change the grinding pad with a finer one designed for polishing. Go through the whole grinding process row by row until the floor is smoothened out evenly. Turn off the unit and the vacuum. Sweep the floor to remove any leftover debris. Inspect for any uneven surfaces and re-grind if necessary.