Heater mats are designed to prevent the subfloor from dropping below 0 Deg Centigrade.
Frost heave is caused when the subfloor temperature drops below 0 Degrees. This can cause significant ice formation in the subfloor over time.
The effects of such formations can be severe.
We recommend that any ground floor situated freezer room over 9m2 (e.g. 3m x 3m) be fitted with a heater mat to prevent this situation occurring.
Freezer rooms fitted on higher floors ( or above a basement / car park ) do not required heater mats to be fitted.