Stupid question on floor finishing / grinding

[Evilcactuar]

I just finished grinding my garage, and spent nearly 30 hours on it. They power troweled the **** out of it, and it took forever to break through the initial finish. I have another pour coming up, what finish do I want to request so that I can grind it in under a day?

 

[Armorpoxy]

We normally recommend a 'hand trowel' finish. Power troweling as you found burnishes the floor and makes the top cream very hard and smooth and not good to accept a coating.

 

[Innovate1]

I am in a similar situation - floor was power troweled. I have someone lined up to grind and epoxy the floor. Any recommendations to make this bond better? How to tell when it is ground enough?

 

[Evilcactuar]

The good news was the concrete looked night and day different when I got through the troweled finish, so I don't think you'll have an issue knowing when you're there. My floor was very dark, almost black, and the areas after grinding are very light grey

 

[Armorpoxy]

Hi, normally a "#80-#120" is a good diamond to use for a nice not too 'scratchy' profile. The profile only needs to be at the microscopic level.

 

[LegacyIndustrial]

If this is not a very built-up flooring system, that you are installing.
We have found that a double etch is sufficient for many systems.
Of course, talk to your representative for best practices.

We would rather a customer do a successful etch than only scratch the surface with a grinder and have an issue down the road.

 

[ConCretin]

I'll always defer to the experts when it comes to these questions but a hand troweled finish makes me nervous. If you give some finishers an inch, they'll take a mile and you could end up with even more grinding.

There are two operations that occur with a power trowel, floating and finishing. Floating determines the localized flatness of the floor (think waviness) and is very important. The second step polishes the floor using steel trowel blades. This is the step you want to go easy on.

I'd want my finisher to float the floor with a power trowel, knock it down and trowel it flat but stop short of a polished finish. I'd call this a smooth troweled finish. The last step could be done by machine of by hand. The goal is to flatten the floor and remove any trowel marks but stop short of hardening and densifying the surface.

It can be a difficult concept to communicate because the terminology varies but it's awfully important to get it right.

 

[Armorpoxy]

That is a great explanation of floor finishing!