Can you use cement board instead of backer board to tile bath floors?

Not cement. I meant cement board. It's like sheetrock but made for damp/wet areas. They use it today as a standard in bathrooms. it's strong and doesn't fall apart if it gets wet the way sheetrock does.

I put it in my mother's bathroom about twenty or so years ago. She had a leak she didn't know about behind the wall where the bathtub faucet was. After a period of time, the wall sort of just 'fell out' and onto the floor of the tub. I cut out all the bad stuff and replaced it with the cement board--it was rather new at the time.

Though my mother is no longer with us, that cement board is, and it's still holding strong according to my younger sister who's there now. It's definitely better than sheetrock for any area that'll be exposed to moisture.

Thanks for your advice though. I appreciate your thoughtfulness! Have a great day.

Linda R

I would still put tar on the underside. No water gets through tar is exactly why they tar a roof. It may not seem conventional, but ever you get a Flood in your tub due to a child who is not conventional either, you will be very glad you used tar.