I am thinking about adding in-floor radiant heat. I have ordered a new wood fired, outside boiler. I am adding a heat exchanger to my forced air furnace, but I want to add floor heat to my garage. Can I cut out cement grooves every 18-24 inches and lay the "pex" tubing and re-cement, or do I need to take out the whole garage floor and start from new? I am trying to save some money by retrofitting, but I am not sure if that is possible or even feasible.