Tanking

[ir50]

I'm replacing a bath with 1200 x 800 shower.
Old tiles are off walls. The wall that is the shorter side of the shower and will have the controls is ply upto about half height. The rest was plasterboard but came off with the tiles. The longer side wall is made of the pink soundproofing board. Tiles came off this quite clean- just need to clean left behind adhesive a bit.

So what do i do with shorter wall?

1. Remove ply and reboard in PB and then tank both walls?
2. Leave ply and fill in rest with ply or PB and tank both walls?

Is there really any point to using a backerboard rather than above if tanking anyway?

Any preference over the tanking matting eg homelux or the paint on tanking shower kit from Mapei apart from drying time

Thanks in advance

 

[iwaters]

Backerboard is a little bit more expensive but a much better substrate. It can hold more weight and will not degrade at all when wet. PB is fine if tanked correctly but given that most has come off anyway I would remove the ply and fit backerboards. Unless you have a very powerful shower or are making a wet room there is no need for tanking on backerboards - the additional cost of the backerboards can be saved here.

 

[ir50]

Cheers for reply. Don't intend removing pink pb as its the sound proofing board with insulation on the back. So its really just the one wall I'll be boarding