Yes, you can put Fiberon decking over a concrete patio in two ways. One is a sleeper system that allows the joists to be installed directly on a solid sub-structure. For non-sleeper applications, make sure there is adequate ventilation and a minimum of 1.4” (4 cm) between the joists and the ground. See instruction requirements for each type of installation.
Minimum joist height is 1.5 inches (4 cm), installed level, in direction of water runoff and directly to a solid sub-structure. Create adequate ventilation for the deck by widening side-to-side spacing between boards to ¼ inch (6 cm) with a maximum of 3/8 inch (9.5 mm) gap. The deck design must allow unrestricted air flow under the deck at the open joist ends for ventilation and drainage. Get sleeper installation tips. Read the blog article for more details
Make sure there is adequate and unobstructed air flow under 50% of the deck. Allow a minimum of 1.5 inches (4 cm) between bottom of joist and the ground. Water must be able to flow away from under the deck. Improve drainage or grade flat areas where standing water may gather. Do not install decking directly to an existing or solid surface. Get complete installation instructions.