HOW TO PATCH & PAINT A VERY PITTED FLOOR
TRANSFORMING A BADLY DAMAGED FLOOR INTO A HI-GLOSS EPOXY SHOWROOM FLOOR
This customer used a 3 gallon set of our Crack & Joint Compound for his 500 sf garage mixed with locally bought Playground Sand after thoroughly acid etching the floor. With pitted floors you need to acid etch because grinding doesn't get down into the pits. He had to acid etch twice to get his floor clean. Then he let it dry 48 hrs. The Crack & Joint Compound can be mixed to any consistency you need, for this project he only added enough sand to the mix to make a slurry. Then using an 18" heavy duty flat squeegee he squeegeed the mixture over the whole floor making sure not to leave any material on the surface. You only want to fill in the pits and cracks.
Our customer was very happy with the results as you will see below. Do not use Underlayment products as they will not hold up to vehicle traffic! So here's a picture after he patched and is grinding down some high spots smooth with a right angle hand grinder. He did a good job with the slurry so only needed minor touch up work. If you need to do a lot of touch up work we recommend renting the floor prep machine from Home Depot, it will make quick work of getting the surface perfectly smooth. 
This is another reason why you want to protect your floor with and epoxy coating, eventually bare concrete will turn into the before picture especially where road salts are used. It's much easier if you coat your floor with a good epoxy floor coating prior to it getting pitted. Once the repair work was done it was easy to apply the epoxy flooring coating.
