Epoxy floor finishes are often a good way to create an attractive and easy-to-clean floor for your garage, laundry room or basement. They can be applied over existing or new surfaces, particularly concrete. Epoxy floors are durable and resistant to heat, rust, acid and salt. They are water-repellant and aren't stained by oil or grease. Additionally, they're available in a variety of colors to match your decor and often can be applied without professional help.
One of the greatest challenges of applying epoxy finish to an existing floor is correctly preparing the surface so that the epoxy will bond well. Grease and oil must be removed, and the surface must be completely dry and as level as possible.
The most problematic issue is when there are remaining traces of cutback adhesive on your floor, and it's not just because it can bleed through into your epoxy flooring. Cutback adhesive is an asphalt-based glue that was common years ago for attaching vinyl or asphalt tiles, and it usually contains asbestos or crystalline silica. You shouldn't try any method of removal that will create dust (such as sandblasting, dry scraping or dry sweeping), as breathing in the particles is extremely dangerous to your health. If you have a lot of the adhesive on your floor, the best option is to cover the older layer completely with a recommended resilient subfloor before applying your epoxy finish. If you want to remove some cutback, you should first check your state or local laws about the removal of this hazardous material.
In some cases, it's possible to use wet scraping techniques to safely remove the adhesive, but it has to be done with the greatest of care; it's preferable (and frequently required) to get a professional to do the job. Guidelines, warnings and recommendations are available from the Resilient Floor Coverings Institute; in particular, see their Recommended Work Practices for Removal of Resilient Floor Coverings.