Be sure the overlay system is tough enough to withstand all the conditions it will confront.
- Is the slab outdoors and subject to weather extremes and freezing and thawing?
- Is it a floor surface in a high-traffic area or subject to chemical, grease and oil spills?
Not all overlays are designed for exterior use and some systems are better suited than others for harsher exposure conditions. Ask the overlay manufacturer or installer to confirm that the material you plan to use will work for your purposes.