Waterproofing plaster wall behind shower tiles

[DH05]

Hi,
I read somewhere that it's a good idea to waterproof plaster walls before tiling a shower or bath, particularly at the bath edge where someday the caulking and grout may deteriorate and let water in. The wall in question is plastered with "bonding" which is very very absorbent of water.

Local shops claim there is no such product and that it is unnecessary.

Advice?
Thanks

 

[Zampa]

Most tilers I have seen just give the wall a coat of pva..this is just to aid adhesion though by stopping the adhesive soaking into the wall to quickly.

You could always give the wall a couple of coats of plaster primer or alkali resiting primer....it certainly wouldnt do any harm.

 

[tylerb]

There is such a product. It is known by the professional tiler (not those who claim to be a tiler) as a tanking system.

Grout will let water pass through and damage the plaster behind.

The tanking stops this by forming a water proof membrane between the tile and the plaster.

Most adhesive manufacturers make one.

You can call PITT technical or BAL technical if you wanted to ask them if what I am saying is true.

TY

 

[masona]

Grout will let water pass through and damage the plaster behind.

Spot on, no grout is 100% waterproof even swimming pool !

 

[Zampa]

Grout will let water pass through and damage the plaster behind.

Spot on, no grout is 100% waterproof even swimming pool !

I never knew that.......always asumed that when a grout says 'waterproof' it means it.....it obviously doesnt make the tiles competely fall off otherwise tere wouldnt be a swimming pool left......but can it do a lot of damage?

 

[tylerb]

A swimming pool is tanked in its own right. Grout and adhesive is not wateproof but can be water resistant therfore the tiles wont fall off in the swimming pool. This is what people dont understand and this is why there are so many problems in peoples showers at home.

Ty

 

[Zampa]

A swimming pool is tanked in its own right. Grout and adhesive is not wateproof but can be water resistant therfore the tiles wont fall off in the swimming pool. This is what people dont understand and this is why there are so many problems in peoples showers at home.

Ty

On the strength of that then.....would that mean a wall would be soaked after every shower?......got me worried now about my own tiling efforts..

 

[masona]

On the strength of that then.....would that mean a wall would be soaked after every shower?

Normally the tiles from the bottom 1/3 up because where it most likely to be wet. Mostly the problem is with plasterboard even with pva sealant and depend how often the shower is being used. You can always tell when it's happening by tapping the tiles for the echo sound effect and black mould on the plasterboard. When I did mine I knock the old tiles off and put in plastic shower panel wall instead for trouble free maintenence, so I wouldn't worry too much about it as there're ways round it such as Aqualpanel or shower panel etc. In swimming pool the tiles behind is wet and only for decorative purpose.

 

[tylerb]

It takes 45 seconds for water to soak the back of a tile in a standard domestic shower by passing through the grout. Sorry to get so technical but this is how tiling has got to be. There are to many tiles falling off walls at the moment and causing serious injuries. Just been to a job where a 7 and 5 year old were injured through marble tiles falling off. People should not attempt tiling unless they have undertaken some form of training, even if it is only a short burst course.

Ty

 

[waynes]

I may have missed the answer here but ill ask anyway..

so if the grout allows the water through what would you suggest be done to the plasterboard before the tiles go on?

and where are we likely to find such a product? just before I start tiling next week....

 

[tylerb]

If you have a look at www.tileforums.com they talk about a tanking system. This is a water proof membrane that you apply to the plaster before tiling. On the forum they will tell you how to do it.

Ty

 

[stevedo]

So if the grout lets water through so quickly, why not put a thin "slither" of bath and shower sealant in the gap between the tile and top up with grout for that perfect aesthetic look.

 

[tylerb]

because i know what i am doing. Tanking a shower will only take 15 minutes to do. How long will it take to fill each grout joint with a sealant that will never truly bond to the tile anyway?

Ty

 

[evanjones]

Sorry to drag up a very old topic...

Is there any need/benefit to "tank" if my walls are real plaster, not plasterboard??