wall soaking wet behind tiles..

[ryoc]

The tile grout on one wall in my shower was going brown. No cleaner would shift it. I treated myself to a Fein Multimaster and cut out the grout. As the cutter was going through, the grout was coming out wet and brown. Then a couple of tiles came away from the wall. The wall behind the tiles, from the tray to about 5' up, is soaking wet. I have stripped about 24 tiles off and the ply behind is starting to dry. Could the water penetration be due to a bad silicone seal on the tray? It would not draw up that much water would it? It only appears to be wet on one of the walls.
Any advice would be appreciated. The ladies of the house are not impressed that the shower is out of order!

 

[Diyisfun]

The smallest of holes/gaps & the water will suck up, capillary action.
You could have a poor bit of grouting.

 

[lancenotalot]

It could be the seal or the grout or a combination of both.Did you mark the damp area?I would cut out a hole in the ply and check behind first.
This is why tanking is always recommended in showers normally up to the height of 1m

 

[ryoc]

Thanks for the replies. The whole area was soaking wet, not localised. It has now dried out and seems fairly sound. I am thinking of sticking self adhesive aluminium foil (mirror backing) to the ply before refitting the tiles. To act as a barrier to prevent further damp ingress through the grout if it happens again. Anyone tried that before? I will also make sure the silicone seal is good too.

 

[Richard C]

I am thinking of sticking self adhesive aluminium foil (mirror backing) to the ply before refitting the tiles. To act as a barrier to prevent further damp ingress through the grout if it happens again. Anyone tried that before?

I definitely would not advise you do that. Tile adhesion won’t be at all good on tin foil if you can get them to stay on there in the first place & then there is the question of adhesion of the foil to the ply to consider. Contrary to popular belief, unless an expensive epoxy based product, waterproof adhesive & grout is only water proof in the sense it won’t disintegrate when it gets wet, it will still absorb moisture which can get into what ever is behind the tiles. Ply is not a good tile base to use in a wet area as it will warp if exposed to any degree of damp, the grout will crack & then things start to get a whole lot worse as the cracks will sipohon water into & behind the tiles. If ply if used in a wet area, it should always be tanked. You could try this;
http://www.bal-adhesives.co.uk/products/wp1-coating
but I suspect whatever you do now will only be a temporary fix.

 

[ryoc]

'but I suspect whatever you do now will only be a temporary fix.'

Sound advice. I will strip the walls out and do a proper job. I have also noticed that there is movement in the shower tray when standing in it. That cannot be a good thing..
Thanks again- Paul