Jobdone!

[Old Mod]

so....to be clear, the real reason for the fail here sounds like Chris used the shower and got the grout/adhesive wet much too soon, so must have exposed a gap???

No haha I wouldn't say that tbh, it may have been a cintributing factor, but not the cause.
The cause was simply a bad install, start to finish.

 

[Stef]

I've ripped out a lot of showers where ply has been used & they were all the same, black mould everywhere.
Wood & water don't mix.
You would have been better using standard plasterboard & tanking that.
I would use wedi or marmox boards (there's plenty more out there) & as they are waterproof then it's only the joins that need taped & you won't have a bit of bother.
I use Mapei Aquadefence for waterproofing showers before I tile & it's very easy to use.

 

[John Benton]

This is what happens when you use ply in a shower

 

[Andy Allen]

Welcome Jack...

 

[Chris1397]

Sorry folks ive been busy. Ok so there are probably many contributing factors as to why it went wrong in 8 months. Having said that i did prime the ply i did butter every tile meticulously, let the adhesive dry for 24 hrs as it advised, i squeezed and worked the grout very carefully into all the joints and sponged off leaving perfectly even grout line and let it dry for 24 hrs as is advised, i thought i had done good! it looked perfect. i still cant believe it failed so quickly.
I have now cut out all the ply up to head height on 3 sides, dwanged and fitted hardibacker, primed, taped joins, twice tanked, and laid new tiles on 100% bed. BUT im still nervous as on closer inspection the cheap B+Q tiles have varying amounts of glazed cover on the edge of the tiles varying from 0.5mm - 2mm! Secondly, i just noticed the bagged adhesive i purchased at B+Q was 3 month past its use by date. Thirdly, because im patching in i am held to the previous pattern and spacer size but i have noticed on the tile box it says "only use spacers of 3mm and >" i however had to use 2mm to match the existing! does that mean the grout dries to quick and loses integrity? should i seal/prime the open grout lines before grouting to slow the suction rate? I hate tiling......

 

[Old Mod]

If u've tanked the shower area u'll be sweet.
Have a little faith in your workmanship, at least u've done things correctly this time.
2mm will be fine, when mixed did u have hard lumps of adhesive present?
If not, I wouldn't worry, the adhesive manufacturers obviously air on he side of caution.

 

[Tile Shop]

Another possibility is that the date on the bag is the date of manufacture and not the use by date. Thats how most adhesive factories do it.

 

[Italy]

Another possibility is that the date on the bag is the date of manufacture and not the use by date. Thats how most adhesive factories do it.

bravo paul
always saw the date of manufacture.