Tiles around bath advice

[mossman70]

Hi,
I've done some searching on the forums but can't find anything that matches my query so apologies if I missed it.

I'm finally getting round to decorating the bathroom (after lots of ear-ache from the boss ) as we haven't touched this room since we moved in.

I have a bath which has a shower over it and two tiled walls exposed to the water from the shower head.

As with lots of posts on here about tiling onto plasterboard I can see first hand the reasoning for not tiling onto this as when I removed the tiles and grout on these 2 walls (to do it properly) the plasterboard had failed in several places and was wet through and crumbling but there was nothing to suggest this when looking at the tiles.

I'm stepping out the stud work and installing hardie backer board onto these, this is so it sits further onto the baths lip (as its quite a deep lip) thus avoiding any fall-back of water then sealing the joints and corners with the waterproof strip and finally tanking it with the paint on kit.

My question is what is the best way to seal the gap between the bath and the hardie board prior to tanking and tiling as I want a super water tight seal??

Many thanks
Sean

 

[PrenticeBoyofDerry]

A good quality silicone sealant with be suitable.
I doubt in your case that the plasterboards have failed, they have done there job, they are not there as waterproof barrier. It is more likely that the grout has failed. Or possible a seal or even pipework if located in this area.

Is your plan to tank up the hardie backers? If so this not really required, in truth neither are hardie backers. If adhesive, tiling, grouting and sealing are done correctly, you will not have water ingress through the tiled area.

 

[mossman70]

Thanks for the reply Prentice,
Yeah I read elsewhere that it was probably the grout that had failed but it showed no signs of this. I was also told by my tile supplier that over time grout and even porcelain tiles are porous and let water through???

I have access to the pipes from the other side of the studded wall (has a large cut-out for access to thermostatic shower mixer) and all is in order with no leaks, but as the plasterboard was foil backed I couldn't see the seepage.

I've also read that tanking was not required onto the Hardie boards but I'm going to belt and brace the job so there is no fear of this happening again.

So sit the Hardie boards down to the bath (bath full of water I presume??) and then tile and just seal with a decent silicone when finally grouted??

Any suggestions on a decent silicone for the job?
Thanks
Sean

 

[PrenticeBoyofDerry]

Dow corning 781

 

[mossman70]

Dow corning 781

Thanks