Do I need to "tank" my new bathroom around the shower area?

Sorry if this has been done to death but googling the group doesn't help me much.
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.
Views welcome.
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IMHO a bit OTT. I have a home made shower cubical which is just tiled direct to ordinary plasterboard. It's really only horizontal surfaces where water might lie that need to be *absolutely* water tight. But in your case that would only be the bath itself?
In my case the cubical is rather wider than the shower tray - to give more elbow room and because of the available space so I made up a strong wood frame to either side and cast in a concrete slope which runs under the walls and is tiled with contrasting floor tiles - and have just a silicone seal between them, and to the tray. It's been fine for many a year.
--
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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Dave Plowman (News) coughed up some electrons that declared:

I agree - for a non wetroom shower, tiles on anything are generally OK, as long as the joints remain basically sound. I'd use silicon for all edge-edge joints and make sure the grout is stuffed in well.
Plasterboard can be didgey if water get's past the tiles on a regular basis, but if the OP uses Aquapanel (et al) or Marmox (et al) (both are waterproof) I can't see any reason to worry. Silicon the Aquapanel for belt and braces.
I don't recall the OP saying what his walls were made of - if brick/block then I'd worry even less.

There's a variation on that which is to box out the wall about 3' up and have a tiled shelf on top (in my case it's 4" deep) - very useful for sticking all the smelly stuff on :) and you still get the feeling of extra space at chest and head height.
Cheers
Tim
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Problem with that would be waterproofing the joints/corners between the Aquapanel if water gets behind the tiles, if you really want a waterproof enclosure.
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*Born free...Taxed to death.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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Ta all. Walls are brick + manky plaster. I'll not bother with a membrane.
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rrh coughed up some electrons that declared:

Personally I wouldn't worry too much. Best efforts on the waterproofing as makes you feel happy, but a tiny leak isn't going to break anything and will find a way out through the brick.
Cheers
Tim
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Tim S wrote:

or through the kitchen ceiling ;-)
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Andy Burns coughed up some electrons that declared:

I said tiny leak, not an impersonation of Niagra!
;->
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Well, yes. As I said, the important point is making sure there are no leaks on horizontal surfaces where water can lie.
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*I must always remember that I'm unique, just like everyone else. *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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