Five factors to consider when choosing a resurfacing system:

1.    What is the state of the existing surface?
Does the current surface have cracks or is it unlevelled? If so, choose a higher-build material such as an underlayment or self-levelling overlay that can be applied at a thickness of 6.35 mm or greater.
2.    What conditions will the overlay be exposed to?
Ensure that the overlay system is tough enough to withstand all the conditions it will be exposed to. Is the slab outdoors and subject to weather extremities and freezing? Is it a floor surface in a high-traffic area, or subject to chemical, grease and oil spills? Ask the overlay manufacturer or installer to confirm that the material you plan to use will work for your needs.
3.    What are the installation costs?
The average cost of an overlay ranges per square metre, depending on the type of system installed. However, the total cost can run considerably higher when choosing an elaborative treatment to pattern a surface or a colouring method (such as integral colour accented by stains or dyes). Ask the installer how these options will affect the final price tag.
4.    What look do you want to achieve?
Determine the colour, pattern and texture you want for your rejuvenated surface and then find a system that can achieve this look. Consult with the overlay manufacturer and installer. Request samples of various finishes and colour selections as well as a portfolio of completed projects.
5.    How much maintenance is required?
Most overlays, when coated with a protective sealer, are very resistant to stains, dirt and grease. They will however still require cleaning to look their best. Ask to have all cleaning and maintenance procedures and lifetime performance expectations put down in writing before committing to a particular care regimen.
Source: www.concretenetwork.com