I am retiling my bathroom and, as it was a mess from removing the old tiles, have removed the bottom half (1.2m) of the plasterboard ready to replace with hardiebacker. To my surprise it seems that the partition wall is made entirely of plasterboard, 3 sheets in total sandwiched together with snot. There is a thin stud along the base and an upright at each end but that is it. Was this common practice? The house is 30 years old. Will I be safe enough using plasterboard adheisive to fix the hardiebacker? Can't really think of another option!