Aquapanel on top or behind shower tray

[lives1]

View attachment tile.pdf

Hi All

I am having some work done on an ensuite shower cubicle and I want to make sure it is fitted without possibility of leaks. So far I have established

1) ply on walls
2) Use Knauf Aquapanel or Hardie Backer boards (some say tanked others not - apparently Knauf recommend not? can anyone confirm - if the board is only moisture resistant then why wouldn't it need tanking?)
3) A lot of people say A or B can be correct (see attached) but as far as I can see if the sealant breaks in A or B water would run down the wall!!!! should a membrane be used between ply and aquapanel attaching to tray so that any water getting through the aquapanel runs back into tray??
4) Is the answer different if the tray has an upstand? Mine is flush fit

Can anyone provide a definitive answer as there seems to be some confusion here and I would rather not have a leaking shower (again!!)

Thanks in advance

 

[Concrete guy]

Not sure why you have Ply in there. I used to fit 12mm Aquapanel direct to studs with 300mm centres. The only advantage you have using the ply is when it comes to fittings being screwed through into something solid.

I would tank. Aquapanel is moisture resistant but it doesn't provide a waterproof barrier, tanking provides this barrier. The only downside of tanking is it can reduce the weight limit of what's being fitted. This is generally only an issue with natural stone.

Onto the tray or not? Well this might actually be determined by the adjustment that's available on the shower enclosure or the design of the tray. I personally used to prefer fitting the aquapanel on the tray and leaving a 2mm gap, fill the gap with slicone then tank over the whole lot right down to the tray.

 

[lives1]

see below

 

[lives1]

Thanks for the reply ATS.

The ply is already installed so I see no reason to remove this really. I am just using normal ceramic tiles so don't see weight being an issue.

So basically you are saying A - but tanking after aquapanel and silicone has been applied. Interesting and makes a bit more sense I guess but even when the silicone is tanked and assuming water can get through the tile/grout layer would the tanked silicone still not crack/perish leaving an escape route for water??

 

[lizzardtong]

I use puraflex pu40 http://www.toolstation.com/m/part.html?p=67949 for everything thats not seen especially to seal shower tray or bath to wall have more trust in it. Then once tiled i use normal silicone that goes with colour of grout.

 

[Concrete guy]

So basically you are saying A - but tanking after aquapanel and silicone has been applied. Interesting and makes a bit more sense I guess but even when the silicone is tanked and assuming water can get through the tile/grout layer would the tanked silicone still not crack/perish leaving an escape route for water??

No, the tanking should be a rubberoid/flexible solution that will flex over time.

There shouldn't be enough movement in the construction that would stress it enough to crack or completely separate.

 

[lives1]

I am now informed by my bathroom fitter that he normally uses Wedi panel - I have had a look at this and it looks fine i.e. waterproof but lighter than cement board and easier to cut/fit. Although tanking is not required I am going belt and braces and having tanking applied. Any thoughts on Wedi?

 

[Qwerty]

Wedi is a great product, but like anything .....it's only as good as its fitment. Fit it and seal it right and the jobs a good un. Fit it wrong and it's an expensive mess [emoji106]

 

[Alan.P]

I never have seen the point of fixing an expensive backerboard then tanking it, as long as the tanking is done right then plasterboard is the way I go.

 

[Aston]

I never have seen the point of fixing an expensive backerboard then tanking it, as long as the tanking is done right then plasterboard is the way I go.

maybe 25 years ago but if you can afford the expensive backer board you will have no mould ingress, higher levels of support for your tile and much better thermal values which is what the whole construction industry is working towards.

ps, [MENTION=20608]lives1[/MENTION], there's is no need to tank the wedi board, just follow the manufacturers guide lines for installation and you will be fine. also, check out schluter kerdi board too.