Hi Everyone
I hope you might be able to help me with this

We install cold rooms within warehouses/shops etc and currently have a rule that any freezer temperature room over 9m2 will require an underfloor heater mat. We also specify that any room (chill or freezer temperature) above a void (ie a basement, upstairs etc) would also require underfloor heating. I do not understand the purpose of heater mats on a ground floor installation where the room would have (for example) a 100mm thick Polyurethane floor (incorporating 12 or 18mm thick plywood on top for strength) being situated onto a concrete floor.

If frost heave is due to cold tracking through to the sub floor is this not prevented by the insulated floor? The cold does not track through the cold room wall panels of the same thickness.

So my questions are:

Why is underfloor heating necessary on a ground floor coldroom installed onto a solid floor (ie concrete) when the room has insulated floor panels?

If it is required, is the 9m2 rule based on any science or is it completely made up? No-one knows from where this rule came...

Is underfloor heating required on any cold room installation above a void or is it dependant upon the thickness of the floor upon which it is installed?

thanks very much in advance

Chris