TBB on top of chipboard?

[EternalOptimist]

Dumb question - I've got a chipboard floor in my bathroom - does the tile backer board go directly on top of the chip or do I need to put down ply on top of the chip?

Cheers

[Oli]

Screw the chipboard down to the joists then lay the backerboard straigh over the top, Im assuming you've already checked that there will be no deflection in the floor (its not bouncy).

Oli