Can I use floor leveling compound on top of backer board?

Question

I am remodeling my bathroom, and plan to put 12 x 12 ceramic tiles down. My sub floor and backerboard are already in place. Unfortunately, I didn't notice the entire bathroom slopes to the center of the house. I need to put a leveling compound down so my tub will be level and allow the water to drain out properly. Can I put the leveling compund on top of the backerboard? I used hardi backer for a backerboard, and pulling it up is NOT an option. Thanks

Answer 1

ok please do me a favor and dont list the the other 2 guys... well the one is half right you can put a floor lever down go to LOWES and buy  LatiLevel. to levle the floor if  and only if ur tub is not a free standing tub do u mortar it down. and if it is not do not use plastic over to of motar. and one more thing make sure u tape ur seams of the hardie any questions email : eone282@yahoo

Answer 2

it's not needed. use the correct knife for the light weight cement and you will love the results. in fact, on a cement slab, you probably didnt need the BB. those 12 inch tiles are very forgiving.

if you pulled your tub, just shim it for an angle you are happy with. (me thinx you are out-thinking this project)

Answer 3

Better to place the tub into a bed of mortar, and level the tub first.  I always put a sheet of plastic sheeting over the mortar, then set the tub, gently pressing down until it is leveled.  Let the mortar cure.  If you need to pull out the tub in the future, the plastic sheeting acts like a release paper, preventing damaging the tub.

After the tub is set and the mortar is cured [12-24 hrs if possible], THEN fill the low areas of the floor around it with a leveling compound. I put the underlayment backer over the leveled sub-floor, but have seen it done the opposite way too.