# How to smooth a rough aggate concrete floor



## lotstodo (Aug 18, 2008)

*Hello, I just poured an exposed concrete floor for a 6 x 8 greenhouse. Everything is fine except the floor is rough to walk on in bare feet, which my wife like to do. Does anyone have any ideas on how to smooth it up. 
I painted on a sealer and used a small grinder but it's still rough, feels like little tiny rocks but I've vacumned up all the tiny rocks/dust before I put the sealer on. I'd appreciate it if anyone has any ideas on how to smooth this floor up enough to walk on it comfortably in bare feet.*

*Thanks*
*Mark*


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## Nestor_Kelebay (Jun 17, 2008)

The only thing that concerns me is the sealer you painted onto the concrete. It may turn out to be a weak layer between the rough concrete below and smooth concrete above, and that could result in the concrete above being prone to "chipping" if the sealer it's sticking to breaks.

One option would be to paint over the sealer (in small areas at a time) with a "concrete bonding agent" and then trowel a skim coat of feather edging concrete over the rough surface you have.

Basically, the difference between a concrete bonding agent and white wood glue is that white wood glue will fall apart if it gets wet and stays wet for a while, even after it had fully dried. Concrete bonding agents have a time period that you can spread wet cement into it, and the moisture from the cement will re-activate the dry concrete bonding agent so that it sticks well to the wet cement.

There are really two kinds of concrete bonding agents. Those that you have to spread the wet cement into before they dry, and those that you can allow to dry and then spread the wet cement into within a certain time period. In the case of the latter, once that time period has passed, then a chemical reaction occurs within the concrete bonding agent so that it becomes unaffected by moisture. Thus, you have a time period from the time you paint the bonding agent on (and allow it to dry) that you have to spread the wet concrete into it. Once that period of time has passed, then the concrete bonding agent becomes unaffected by water so that it won't stick to wet concrete, but nor will it come apart even if it stays very wet for very long.

Also, cement will come in bags that say that you can spread it from 1 to 1/2 inch thick, from 1/4 to 1 inch thick, etc. The restriction on the minimum thickness comes from the aggregate inside the concrete mix. If the maximum stone size in the aggregate is 1/4 inch in diameter, then the minimum thickness you can spread that cement is 1/4 inch thick. You need to get a cement mix that has very finely ground sand in it so that you can "feather edge" it, or spread it very thin.

Grace is a company that makes all kinds of construction materials, including cements and bonding agents. Grace Daraweld C is a concrete bonding agent I've used and have had good results with. With Daraweld C, you have to spread the cement into the Daraweld C before it dries.

You might want to open your yellow pages phone book and phone around to find out who sells Grace construction products in your area. They will sell you Daraweld C and a feather edging concrete mix to use with it. I know Grace used to make a cement mix called Daracrete, but it's not on their web site any more.

If Grace doesn't make a cement that you can spread really thin, then you might have to use something from Home Depot, but I expect that whomever sells the Daraweld C will also be able to advise you on a concrete mix that you can use with it that can be spread very smooth.


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