Looking to build approximately a 5000 sq ft walk in freezer in a warehouse on top of the existing concrete floor. It is for cold storage (-25 C).

I am going to put a vapor barrier on top of the existing concrete floor and am going to put 6" thick Urethane insulation and another vapor barrier on top with 5" of concrete on top.


Now, do I need a heating cable or a heat source before I add anything to the existing floor?