I am currently getting ready to lay my cement board down (Durock) in the bathroom floor that I am remodeling. I was trying to save some time and not remove my door frames and just tile/cement board under them. However, on one side there is plent of room for me to use 1/2" Durock and tile, while on the other side it is a tight fit and I will most likley have to "squeeze" in the tile/cement board combined thickness. My question is, is it ok to use 1/4" Durock on the floor under my tile or do I have to use 1/2" Thanks for the help