Aquapanel for shower enclosure

[andyj941]

Hi I'm in the process of ripping out a recessed shower enclosure that was leaking and the tiles were in need of updating. As I've took the tiles off the plasterboard underneath was destroyed and in some places black with mould. I'm going to replace the plasterboard with aquapanel then get a new tray with upstands and tile over this, then reseal with silicone and hopefully it will never leak again.

My question is this - I want to join the aquapanel and pb at the centre of the studs and secure with screws. I'm ripping off the old pb now but how do I cut it so I've got a straight line to join with the aquapanel whilst it's still on the wall?

Also the aquapanel instructions say to leave a 3mm gap between panels and fix with tape and adhesive, is this recommended for the join with the pb?

Thanks

 

[RoughWaters]

Simply cut pb with a straight edge and stanley knife cutting into it a bit more each time.