Today we’re going to show you how to grind concrete floors. Why is it important to grind
concrete floors? Well, if you’ve got a superficial contaminant on the top of concrete, like thinset,
paint, or God knows what else, you need to remove that before you can put your new flooring.
So we’re going to share what tools make this much easier and safer. We’re also going
to go onto a mistake that we made that we don’t want you to make on your project.
The first thing that you need is a really great HepaVac. This is the Fein HepaVac, and
there’s a reason why we really like it. The cool thing about this HepaVac is the fact
that it has an outlet. You can plug in your power tool—in this case an angle grinder—and
then turn the power setting to the outlet, the little logo right here. What that does
is it turns on the HepaVac when you turn on your power tool. It almost goes without saying,
but if you’re going to grind concrete floors, you need an angle grinder. This is Fein’s
WSG 7. It’s a 4 ½-inch angle grinder. But this isn’t the most important tool that
you need. Arguably, this is the most important facet of grinding concrete. It is a dust shroud.
This is Fein’s surface grinding shroud, and you can use this for grinders up to 6
inches, and you can also use it up to wheels up to 5 inches, which brings me to the next
tool that you need. This is the thinset removal bit. This is a
grinding wheel, specifically for removing thinset—you guessed it. And you can use
it to also remove paint and any other superficial contaminant on top of your concrete.
When you combine a HepaVac, a grinder, the thinest removal bit, and the surface shroud,
these four components make grinding concrete much safer and faster. But that’s not the
end of the story. Admittedly, sometimes we forget our personal
safety equipment, but whenever you’re grinding concrete floors, you don’t want to do that.
So make sure you got some safety glasses, hearing protection—I like these guys; they’re
like, I don’t know, $8; you can find them on Amazon—and then our personal favorite
piece of protective equipment, is the Sundstrom silica dust respirator. Probably the best
$50 you’ll spend on a respirator. This is great, and you can use this to grind down
concrete, tile. Anything with silica in it, this is going to prevent that silica from
getting into your lungs. So make sure you get one of these.
In this bathroom, we had two specific problems with the concrete floor. Number one, we did
have some paint overspray along the perimeter of the floor. It’s never good especially
if you’re going to be bonding a self-leveler to the concrete, like we had to do in this
example. Second, we did have a little bit of joint compound here and there. Not typically
a big problem, but you definitely want to get all of it off of the surface of the floor
because it’s going to be a bond breaker. Now, if you’re removing ceramic or porcelain
tile from concrete, chances are high that you’re going to have thinset residue on
the top of the floor. So you need to remove that. This is a great method. This method
will also work if you have a little bit of residue if you have like a vinyl tile on the
surface of the concrete. Now, the first thing that you need to do is
remove all the dust and any contaminants that are just resting on the top of the floor.
Secondly, you’re going to want to install the dust shroud onto your grinder. Now, the
cool thing with this one is it will work with a variety of different grinders. So if you’ve
got DeWalt, Makita, Milwaukee, this dust shroud will work with all of those grinders. This
dust guard comes with a metal connector. The connector is right here. There are three screws
that hold it onto the shroud. You can see it from the top as well. Basically, if this
connector doesn’t work with your grinder, you can swap it out for one that does work.
You’ll have to remove the guard from the grinder, and then this slides into place.
Sometimes it can be a pain in the butt, so you just have to loosen the screws to get
it in place. As you can see, that’s how it fits onto the grinder. All you need to
do is tighten these screws right here. There are only two screws on the front. And then
finally, you want to install your thinset removal bit into the grinder. This thinset
removal bit simply just twists onto the spindle of the grinder, and that’s it.
There are some additional features about this HepaVac, which make it great. First, the power
cord. Super long. So if you need to have the HepaVac somewhere and it’s not anywhere
close to an outlet, not a big deal. The other cool feature which we like a lot is the length
of the hose. And this allows you to keep the HepaVac out of the room, especially a bathroom
when you’re grinding a floor or you’re cutting tiles.
We started this project in the corner of our bathroom. We had the thinset removal bit facing
downward and then turn the angle grinder on the full power and engaged the bit into the
surface of the concrete. There were no issues whatsoever removing the paint overspray or
the joint compound. And as you can see here, the nice thing with this surface guard is
it’ll fit tight up against the wall, door casings, or adjacent flooring.
We were really impressed with the dust removal capacity of not only the dust shroud but the
HepaVac. It’s awesome. We highly recommend this setup if you don’t currently have one.
So make sure you check it out. Now, there are two mistakes that we made.
We don’t want you to make those. Number one: when you’re grinding the surface
of concrete, you’re going to have some residual dust that remains on the surface. When you
see that residual dust, vacuum it up so that you’re not hitting it with the thinset removal
bit. When you hit it with the thinset removal bit, you’re going to send a little plume
of dust up in the air, and that’s never good. So, tip number one is always remove
any residual concrete dust that remains on the surface of the floor.
Tip number two: if you feel your angle grinder getting hot, allow it to cool down for a minute
or two. In this case, we were kind of on a tight schedule, and we kept going to remove
all of the paint off of our floor and any of that joint compound. Unfortunately, the
angle grinder actually caught on fire, which we didn’t anticipate, and that’s what
you see here. It’s not actually dust, but it’s smoke from the angle grinder motor.
That totally stinks. So don’t make that mistake. If you feel the angle grinder getting
hot, just stop and allow it to cool down. If you have any questions, let us know down
in the comments. We’re happy to help out with tool suggestions. If you’ve got your
own tool suggestion, let us now as well. Thanks for watching, and we’ll see you in
the next tutorial.