My refurbed bathroom will have an over-bath, gravity-fed but not pumped Aqualisa shower. There is about 5 metres head of water. Cold feed is 22mm direct from the roof tank and hot is similar from the top of the cylinder about 20cm away directly behind the wall where the shower valve will go. So this may not qualify as a "power shower" (whatever that is) but if it is anything like the old Aqualisa I took out, there will be a strong flow at least as good as the pumped shower on the floor above. I will be using Aquapanel on the three walls around the bath. I'm looking for advice on whether it would be a good idea also to use a tanking system such as that from BAL (painted-on coating plus mesh tape for corners etc) or Impey Tilesafe (self-adhesive membrane), or just put the tiles on directly with appropriate water-resistant adhesive and grout.
I'm not that worried about extra cost (though it's quite high) or work. What I don't want to compromise is that lovely smooth and even surface for tiling which I'll get from the Aquapanel. I fear that the BAL system might do that as it will have slightly raised areas and then a thick painted-on and possibly uneven coating. The Tilesafe is a thick membrane which might well make internal corners etc totally waterproof but make it difficult to tile up to them properly afterwards.