backer board

[sweaty sock]

have used this loads of times on chipboard but have a small floarboarded bathroom - can i still use it with some fastflex underneath to bed in - i dont want the floor height to change much :yikes:

 

[White Room]

Make sure your've got no bounce on the floor and use a 6mm board, I use a spf rapid and screw the board to the floor boards not thru them

 

[sweaty sock]

thanks whitebeam _ there is a small patch that is flexing and i plan to fix to joist to stiffen up before fitting backerboard