Advice Requested on tiling a wet room/bathroom

[Steve H]

Good afternoon Gentlemen,
I would appreciate any advice you can offer on tiling this wet-room/bathroom. I have a little experience with tiling.
The room will be about 1.7mtr square and on the shower wall it will be 3mtr tall and on the shorter wall it will be 1.6mtr tall, it is fitted into a roofspace. The joiners have almost finished fitting it out with a water resistant backer board. The plumber has already fitted the wet-room tray.
My intentions are to use a BAL wp kit to seal the joins in the backer board, corners and around the edges of the backer board on the floor. Will the tape that comes with the kit be sufficient for this, particularly in the corners and where the board meets the floor/tray?
I anticipate a problem in that the floor has 6mm board on it and as such is 6-7mm higher than the tray. The tray will be tiled with a slate effect porcelain mosaic tile in 300mm squares with each piece being 30mm. I have sufficient mosaics to have at least 1 full mosaic tile on the floor level, outside the tray. The rest of the floor and the walls will be tiled with a similar full porcelain tile 600x300mm.
There is a small gap between one edge of the tray and the floor, about 3-4mm. I have in mind to fill this with some of the BAL SPF adhesive before tanking at the same time, I plan to create a fillet from the higher level of the back board down to the tray, over about 100-150mm using the adhesive as a filler, I hope this makes sense to you, even if its not the correct method for joining the 2 levels.
I then intend to tank the wet area, using the kit, tile the walls, starting 200mm from the floor, then tile the floor, starting with the mosaics and working out from them. Once all set, I will cut and insert the bottom tiles. Grout and then seal the corners with Silicon.
Here are some photos of the room and areas mentioned.
My questions are:
Does my plan sound feasible?
Will the tape that comes with the WP kit be sufficient for the corners and edging the floor to the wet tray?
Is my plan to fill the drop down from the floor level to the tray with adhesive ok? If not what should I use.
Thank you in advance of any advice offered

 

[Dan]

I can't remember the exact measurements but British standards states that over a 2m length there is meant to be no deviation either way more than about 3mm or something like that, so no, that's quite bad. Varying thicknesses of adhesives that much will mean A) you have a lot more weight than is allowed on plasterboard in certain areas and B) your adhesive choice becomes more important and restrictive. As you don't want shrinkage which can crack tiles.

Tanking wise: not sure what he has used there that sounds weird.

 

[Dan]

Also, first pic bottom right, what's screws are those?

 

[Steve H]

Thanks Geoff and Dan, I was beginning to think this may need taking apart before putting together again. Just to clarify Geoff, my intention was to tank the wet areas, tray and wall with BAL WP1 tanking kit, on top of the resin, but I have no experience of this type of finish and I am not certain that the BAL kit would adhere to the resin. The screws are 40mm brass (coloured).

 

[SJPurdy]

You are thinking right. Wall so bad easier to redo it flat rather than try to plaster it flat. If the surface is so bad what is the fixing underneath like? To be flat enough to tile it must not be possible to slide a 3mm spacer underneath a 2m long straight edge placed anywhere on the wall!

You will need to know what the fiberglass resin stuff is so that you can check with the BAL tech help people if their tanking system can be applied over it. I wouldn't risk it without their say so.

 

[Chalker]

The walls will need straightening. But as for the showere area I would tape all the joints and tank the whole area with ardex wp. It sticks to anything.

 

[One Day]

And this gentlemen is exactly why we need regulation on wet area preparation. All that hardibacker is totally and utterly pointless and all the effort that's gone in so far is pretty much wasted. I could cry...

 

[Flintstone]

As above and I have also spotted that the tray appears to be much lower than the rest of the floor area which is a big problem

 

[One Day]

Steve, if you really are going to press on with this, I would do the following:
Sand down the fibreglass well with a rough paper, to aid keying.
Get 2x Ardex WPC kits and tank out the wet area. Scrim tape the corners and board joints and go over again with Ardex WPC.
Drill some weep holes into the little plastic upstand around that marmox tray, and don't use less than 50mm mosaics on it.
Good idea too to use an epoxy grout on the tray.


AAAARGH!!! Just makes me so mad to see HB on the walls!

 

[Steve H]

Thanks all for your advice. It has frightened me off, mainly cos I'm sodding off to the Algarve in the camper van in a couple of weeks and I wouldn't want to leave a mess or a half finished job. I know a very capable and experienced tiler, who will know exactly how to finish this job and at the end of the day the neighbour will be happy, which is the aim after all.
All the head scratching and banter on this forum has whetted my appetite and I will be getting my trowels dirty when I return. Thanks once again for sharing your knowledge.

 

[average]

Fill the walls out with tiling addy and as for the 3mm rise between floor and tray, youll take that out with tiling addy aswell