The WIB boards will save you money by acting as a very efficient thermal barrier. Heats up times in our testing facility were cut down from 2.5 hrs. to just 25 minutes. With a 78% fast ramp-up time, your system will save you 71% in electrical usage.
All surfaces should be thoroughly cleaned of all dirt and debris. When installing over an existing concrete base, it is important to remove all traces of existing finishes, contamination, etc. to allow for a clean surface.