9 Concrete Grinding Tips to Make a Slab Level

Throughout this blog post, we will go through 9 Concrete Grinding Tips to Make a Slab Level.

#1 Save That Slab

#3 Diamond Grains Do The Cutting

The cutting surfaces of these grinders are diamond grains held by “segments,” the raised metal parts of the wheel. An aggressive wheel, which can take down 1/4 in. of concrete or more, grinds away material faster but leaves a rougher surface. A less aggressive wheel removes smaller amounts of concrete and leaves a smoother surface.

Here’s the rule of thumb for choosing a wheel: The more surface area it has, the less aggressive the wheel. Choose an aggressive one to remove high, long ridges or large, rough areas of concrete and a less aggressive one for tasks like cleaning up tile thin-set residue from a wall or prepping for an epoxy coating.

#4 Always Wear Safety Gear

Plan to deck yourself out in safety gear: hearing protection, safety glasses and a respirator. The high-speed machines are loud and can send concrete rubble flying from the grinding wheel. Grinding concrete also releases fine silica dust, which can cause health problems. Always wear a NIOSH-certified N95-rated respirator. Check the seal with this easy test: If you can exhale and inhale sharply without air escaping, you’re good to grind. If you have facial hair, even a bit of stubble will ruin the seal. Go ahead and shave—it will grow back!

#5 Keep The Machine In Motion

While you’re grinding, keep the cutter head moving, especially with a large floor grinder. Pivot the machine on its wheels, moving the cutter head in an arcing motion. If the cutting surface is riding on only one edge, work the machine in small circles to flatten out the surface.

#6 Choosing A Dust Control Method

There are two great ways to keep the dust from going wild. You can use a hand pump sprayer to soak the floor with water as you grind to keep the dust down. But you’ll have a messy slurry that will need to be hosed away or sucked up with a wet vacuum.

Or you can rent a heavy-duty vacuum (regular shop vacuums won’t be able to keep up) to hook up to the grinder. It will also do a very good job of dust removal, but you’ll still need to put up walls of plastic sheeting and cover nearby vents. The choice is yours, but remember to wear your respirator either way!

#7 Nibble At A Heave

For a heaved sidewalk or cracked slab, tilt the grinder slightly and remove the meat of the concrete and then feather back the high spot. You may never get toe-stubbing heaves completely flat, but you can lessen the hazard. When tilted, the dust shroud can’t catch all the dust, so you’ll need a second hose and a helper.

#8 Grinding To The Edge

Never remove a dust shroud to get close to a wall. You’ll increase your exposure to nasty silica and remove a safety barrier. To grind near walls with a convertible dust shroud attached, push the open end of the dust shroud against the wall and make steady, shallow passes. Be sure you don’t dig the edge of the wheel into the concrete as you move it back and forth.

#9 Mark Where To Grind

– Trace the High Spots

Outline the space that needs to be ground. Using a level or other straightedge, find where the high spot meets the flat surface. Balance the straightedge on the high spot and mark where the ends of the level are equidistant from the ground and trace around the high spot. This can be done by eye; it won’t be perfect, but it will be a good start.

– Check Your Progress

Start grinding the concrete on the crown of the high spot and work your way toward your marks. When you feel you’ve made progress, use the straightedge again to check for flatness. Retrace the high spots and grind them down. Repeat this grind-and-check process until the high spot is gone.