Waterproofing shower area - which method?

5 Sep 2016
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United Kingdom
Hi All

I am installing a shower tray and pivot door inside an alcove that is constructed from three stud walls. I did this once already but had to rip the whole lot out recently as a result of various leaks that occurred. It lasted twelve years so I don't think it was a bad result for a first time DIY effort but unfortunately the water damaged one of the underlying floor joists so I had to go to much trouble this weekend to replace that! Needless to say, I don't want this to happen again so here I am seeking advice!

In the original cubicle, I chose to incorporate some glass blocks into one wall. I had difficulty coming up with a method of maintaining a robust seal at the intersection between the blocks and the tiles in the inside of the cubicle. I think this was the main area that leaks occurred, leading to the majority of the backing boards rotting away (I used marine ply at the time, for the backing boards). The other mistake seemed to be the use of mosaic tiles for some decorative borders inside the cubicle. This seemed to provide more areas for water to get behind the tiles (more grout to crack an leak), I found wood rot mainly in these areas. Just for reference, the old shower tray had an up-stand that I tiled over, this seemed reasonably effective.

So opinions please?.....

1) This time around I intend to keep the design simple by scrapping off the glass blocks and instead installing a shower light/fan in the ceiling.
2) I intend to use Hardibacker instead of marine ply.
3) I intend to use a tanking solution of some description (more on this below).

Assuming that I am going down the right path here, my main query is regarding the tanking. I'd like to use a standard tray without an up-stand. I've been looking at the Classi Seal flexible up-stands, they do two types, a standard version and Classi Plus. Classi Plus seems to be intended for use in conjunction with their tanking kit. With the standard up-stand, I don't see how, in the event of water penetration to the rear of the tile, the up-stand prevents water passing between the Hardibacker and the up-stand? The Classi Plus seems to require bonding with a layer of tile adhesive which makes more sense to me from a waterproofing perspective?

Tanking - I've seen paint on style kits that use fibreglass matting over the joints and in the corners. I've seen kits such as Classi Seal waterproofing kits that seem to use large mats bonded to the walls then tiled over. I want to go belt and braces on this to ensure there are no problems this time around but have no idea what method may be most suitable for my application.

I really need some opinions/advice and would be very grateful for some help please.

Links to Classi Seal items that I referenced: http://waterproofyourbathroom.com/product/classi-waterproofing-kit-for-shower-trays-and-baths-6-5m²-kit/



The other stuff that I've seen is paint on type such as: http://www.wickes.co.uk/Bostik-Wate...W4Egvt9hadgNvz2d2M8aAt-yEALw_wcB&gclsrc=aw.ds
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Maybe. If this is the case, apologies, could a moderator please move to the correct forum please?
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Thank you. Looks decent.

Don't suppose anyone has a link to a long term test for this product please? It took about 8 years for my last shower to start showing signs of leakage.
Can't help unfortunately but it's what I use on all my installations. Mapei make quality products.
May I ask how long you have been using this product for? I guess it goes without saying that you've had no call backs, you wouldn't be recommending this stuff otherwise.
I'd say I moved over to tanking all wet areas about four years ago. No failures as yet. It's a non biodegradable membrane with mechanical protection (i.e. behind tiles). No reason to think it should fail.
My shower tray and walls are fabricated from solvent welded ABS sheets. So far 6 years of no leaks. Minimalistic look but fuctional
Prefer shower panels, never leaked and looked as good as new even after 20 years use.
Every shower failure I’ve seen has been tile on plasterboard .

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