Where does excess water go in tanked system?

[alvarez]

Hi All,

Fantastic forum, but I couldn't find an answer for the question above.
As no grout and adhesive is waterproof (is water resistant - stays as it is and doesn't disintegrate) it will eventually let water in and cause the damage (like in my case: tiles on the plasterboard not tanked) leaking through the floor and into living room below. The walls in my bathroom were originally compressed straw solid 50mm thick panels. One of them got soaked and repairs got done by previous owners - they put plasterboard and tiles on top of that. That also lasted only couple of years and now most of the bathroom needs a full rebuild (I'd like to post some photos but the data limit is ridiculous 10kB...)
The question I've got is when I rebuild the walls around the bath with some sort of cement board and then tank it, where that excess water will go, as the grout will let the water in eventually but not causing any damage. Water will be dripping down the wall and on the floor then what next. Would it stay there and evaporate? Would you tank it only to the level of the bath?

Cheers

 

[Qwerty]

Welcome :welcome:

Tanking can mean waterproofing all walls and floor in a room (or part of), with all joints and corners tanked also. Imagine a swimming pool where it is all waterproof.

Or, say in a shower area....tanking of the walls down to the tray with the tanking just lapping down into the tray (or edge of bath if it is a bath). Any water ingress through the grout is rarely anything more than a tiny bit of moisture so it will just escape back out the way it came in through evaporation or it will track its way (as water does) to the lowest point and escape that way. A neat Silicon joint will of course prevent this, but it will find its way out again via a grout joint. In all honesty when applied properly, most modern grouts are fine at keeping water out. It's usually poor tiling that leads to water ingress. I still always recommend tanking though as the initial cost far outweighs the potential cost if there is any failure (plus it's what my business is all about!)

if you only tank the wall & not lap it down onto the tray or bath then yes it will drip behind and cause damage if it ever got through.

Send pics to my business email below if you like and I will try to upload them for you

 

[Qwerty]

See attached photos of a fully tanked enclosure

 

[alvarez]

Hi,
Thank you for the reply.
What sort of lapping is required and what does it consist of? I'm sending the images of the disastrous bathroom.
Thanks

 

[area tiling]

You could always use epoxy grout !!

 

[Qwerty]

Here are the photos.......

 

[Qwerty]

What sort of lapping is required and what does it consist of?

Taking the tanking down over the surface by about 5-6mm. Most tanking kits available consist of a gum & roll kit. It's the tanking roll that is used to lap over the edge

 

[Time's Ran Out]

Just use a Wedi board or similar, and epoxy grout, sealing all corners and joints.
Check around your shower controls and make sure there is no flex in your bath if on a wooden or straw floor!
Id have been the pig in the brick house!

 

[Qwerty]

Pic 6 is my favourite.....exposed wires & floating shower mixer, the stuff dreams are made of!

TJ is right....tanking board is a great solution, but you will still need to make good a seal between the board & bath to ensure full tanking integrity.

 

[alvarez]

Would it be possible to use 50mm thick wedi board and basically slot it in where straw panel used to be? The only concern would be how to incorporate water pipes into that board... The pipework wasn't fully going into the straw panel and rather on the angle, touching the edge of the bath and then gradually going deeper in (pic 4&5). Or to go with hardiebacker and then cut the slot in for the pipework, plaster over it then tank the lot with BAL.
It's going to be my first big DIY job and I'm much more comfortable with computer programming than wall builing... :lol: It looks like I've bitten more than I can chew.:mad2: