Design - Dealing with ground water?

It must be appreciated that the floor system is not designed to overcome groundwater problems. Any likelihood of flooding of the sub-base by rising groundwater must be completely resolved before attempting to install the floor system. This is of course also the case for conventional concrete/DPM slabs. 

We would suggest that a drainage engineer should be consulted, who will be able to identify any local information which would indicate the expected height of the water table during prolonged periods of rain or following heavy snow. Once you are satisfied that the groundwater issue has been resolved, the floor can be installed and will function as designed to a given level of insulation and with the capacity to resist water ingress.