Was laying 6mm Backerboards today. I used HardiBacker screws, and was screwing into 18mm floorboards. I had my JCB Livewire stud & metal finder with me and I used it because I was scared of drilling holes into pipes & wires etc in the bathroom. The detector was bleeping all the time and it took me ages to finish the job screwing. Bearing in mind that I put a screw ever 8" or so. What detectors do you guys'n'girls use? Do you have any tips? I also found that the screws did not always finish flush with the hardibacker. Cheers Sean