Attaching water backerboard around bath and shower?

[dude_diy]

Hi thanks in advance for all replies. I'm currently renovating my bathroom and attaching waterproof backer board around the bath which will be hit with water as the shower is in the bath.
On one corner I intend to attach the board to new stud work. But on the main bath wall I was thinking of just screwing the backer board through the existing plasterboard. I would screw the board deep enough to pick up on the brick work.
My question is, is this okay or should a batten the wall first or even dot and dab it?

thanks

 

[noseall]

What we do is dab it. We then go back to it, once the dabbing has set and supplement the fixings with screws and plugs.

Be deliberate with the dabbing spots and memorise where they are, then apply the mechanical fixings in line with the dabs.

This dabbing method allows you to true up the boards with ease, as all the dabs are doing is acting as spacers and will not hold the board on their own but long enough to get a screw-fixing.

 

[dude_diy]

Thanks Noseall, much appreciated. thanks for the early reply, going to crack on today. Cheers mate

 

[dude_diy]

What would you say in the minimum thickness of the dabs, Im trying not to loose to much space in the room? thanks.

 

[1john]

the size on the dabs depends on the trueness of the existing wall, if it is spot on or near enough then you can use small dabs.

 

[Micilin]

the size on the dabs depends on the trueness of the existing wall, if it is spot on or near enough then you can use small dabs.

IN addition to this, check the wall first with edge/level so that you know where to have the thicker dabs if needed. ie give yourself a 'map' of the wall , whigh spots, out of plumb etc.

 

[dude_diy]

Thanks guys, for the repiles. The wall isn't that badly level. Just one small area is out buy a few mil. It would be ideal/ easier/ less work for me to just screw the backer board through the layer or dodgy plaster and pick up on the brick. Would this method be bad practice? bearing in mind the wall isnt that out of true? any further comments?

 

[1john]

i suppose you could trowel it on with a 10mm notched trowel in vertical strips at about 400mm centers and tamp the board into the adhesive as normal.