I don't recommend hardwood floors in full bathrooms. Powder rooms and kitchens, no problem. Wood and water don't get along and the resultant problems are not worth the trouble. It isn't about water getting on the flooring, it is about the humidity changes in the room on a constant basis, ventilation or no. So, hard to take care of...yes. Use a nice stone tile. Regarding radiant heat and wood floors, yes, it is doable. We've done them before using Wirsbo PEX tubing in the Wirsbo grooved ply panels. They have an aluminum reflective layer on the bottom to "aim" the heat up. We used quarter sawn white oak for a more dimensionally stable material and laid it diagonally so the PEX tubing would be traceable at all times. Electric heat mats? I think maybe not. With a floating floor system it could work..but who wants to hear that tap, tap, tapping all the time.

I have wood floors in my powder room and one of my guest bedroom baths.........I love them, so easy to keep........I have tile in the master bath.........wish I had put wood floor in my other guest bath that I have tile in............the old saying, no wood floors in baths.....but taking up tile would be a pain also.....

Wood flooring is a popular surface option that is installed over electric radiant floor heating! You can check out our TempZone™ system that can be installed under wood, stone, or tile or you are looking into installing floating wood floors, you can install our Environ II system! http://www.warmlyyours.com/en-US/floor-heating

Thanks for all the great information. Probably not the best idea.

Ironwood Builders: I'm thinking of having a floating wood floor installed in a new home built on a slab with in-floor radiant heat. What do you mean about "hearing that tap, tap, tapping all the time"? Thanks. (BTW, I lived in Forestville many long years ago!)