Stott
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| posted on 23/4/12 at 01:57 PM |
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How to seal a shower tray up
HI, I posted this on the tilers forums but haven't been given a reply so I thought I'd ask on here instead, hope it makes sense! It just
doesn't seem logical to me that you create a waterproof substrate that drains onto the tray yet fill up the gap it would drain out of with
sealant.
I can see the merit in sealing a non tanked shower as you are relying on the surface of the tile and the grout to stop water and to drain into the
tray, but in a situation like mine using natural stone, where water can reasonably be expected to get behind the tile, I don't get it.
Help me LCB! 
I'm in the middle of a tiling job at the moment.
I've removed the plaster from the walls, primed all with bal apd, tanked shower area with wp1 and tiled with travertine brick mosaic using bal
rapidset flex (white), I've got norcros jasmine grout ready to complete it, and hg inpregnator too.
I masked the tray up and lipped the tanking onto it so it sits just behind the tile, but I'm confused as to the sealing of the tray.
If I seal between the tray and the tiles now, then what happens to the water that goes through the tiles and runs down the tanking? It seems to me
that it would just sit there or have to make its way back through the tile/grout to drain off. In fact I read a post somewhere where the guy was
complaining that his tray to tile seal was going mouldy but when he scraped it out to redo it water streamed out that was being held behind the
tile.
Can anyone explain this for me please?
Cheers
Stott
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JoelP
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| posted on 23/4/12 at 03:30 PM |
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As i see it, not a huge amount of water will soak through even a porous tile. However if its not sealed at the bottom, then a large amount of water
will splash onto the bottom and soak in. The grout will always be a bit cracked at the bottom because there is no reasonable way to completely prevent
the tray moving/flexing. So i myself would have done a through seal before tiling (between tray and wall/board), and then just a tidy one (with
masking tape) after tiling. Provided you dont end up with cracked grout lines further up the wall, then you wont have much water behind the tiles, and
any that does get there can seep out just above the seal, or evaporate inbetween uses.
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zilspeed
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| posted on 23/4/12 at 04:59 PM |
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My own approach.
Install tray.
Seal between tray and perimeter substrate prior to tiling.
Tile walls.
Seal between tray and tiling.
Not sealing before tiling leaves potential for leakage at the tray, which as Joel rightly says, will certainly move.
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britishtrident
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| posted on 23/4/12 at 06:58 PM |
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Best to use a quadrant shaped ceramic beading at the bottom of the tiles so the water running off the tiles gets diverted into the tray rather
than the between the tile and the tray. You can then seal between the tray and beading with silicone.
B&Q sell the beading in various colours,
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Stott
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| posted on 23/4/12 at 07:45 PM |
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The tray went in on a bed of compo and was sealed to the walls
Then the area was tanked down to the tray overlapping it so that any water runs onto the tray, this is a total waterproof rubber membrane once set
Then I tiled to that leaving the required gap for the tray to tile silicone bead, and when I grout the area I'm not doing that last bit or the
upright corner in the shower as these need siliconing as they will move
My confusion is that you effectively line the Walls with rubber so the tray gets all the run off then you seal up the water exit path, but I take your
point Joel, it's not going to be a huge amount of water even though it's classed as a very porous tile, but it's on plasterboard and
also they are 2x4 brick mosaics (unfilled) so there's loads of grout lines to seep and holes through the tiles (which will be filled with grout)
- that's why I tanked it.
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