Tiles Darkening?

[biffa69]

Can anyone offer any advice on this one.

A customer has come back to me complaining of tiles becoming progressively discoloured in her new bathroom. It is the course above the bath (the wettest area). They are an 'off white' ceramic tile and have been on the wall for about 10 weeks. The wall is internal brick, dry-lined with plasterboard, tanked with BAL WP1, adhesive is Granfix Flexi-wall (AA), and the grout is BAL Micro-ban (all the same as I usually use for wet areas).

I was shocked when I saw them, they have definately darkened in appearance since they were fixed, but there is no point in re-doing them until I get to the root cause.

Any help/comments most welcome.

 

[trevortine]

What colour is the adhesive?

 

[Concept PHT]

And did you use a bath seal / silicone seal around the edge of the bath? It could be water creeping up the back.

Did you fill the bath with water before installing / applying if you did? What could be happening is the bath drops away from the seal when its full of water and occupied with a person thus letting water behind the tiles.

 

[L & R CERAMICS]

i thought id leave this one for u

 

[biffa69]

Hi,

Adhesive is white and yeah, I did fill the bath before fitting a bath seal strip and then siliconing but there is sod all movement on the bath anyway as it is cast iron. I will have a closer inspection on the silicon sealant though because by the way they are darkening , it definately looks like moisture is getting into the tile.

Come to think off it, I used a different silicon on that job to previous jobs. Screwfix have changed to a new line called 'No Nonsense'. Anybody else tried it?

 

[Traxman]

What size are the tiles?
What trowel did you use?

Are the tiles porcelain?, some of the cheaper porcelain tiles are porous and need
sealing before fitting then resealing after grouting.

Maybe you could test a tile by spraying water onto it and seeing if any of the water soaks into the tile.

 

[biffa69]

Hi Traxman,

Tiles are 250mm by 330mm, trowel was a Benson V-notch giving 100% coverage and they are not porcelain, they are ceramic.

It definately looks as though they are taking in moisture - the darkening starts at the bottom and works it way up the tile.

I am going to have a closer look at the seal around the bottom. Assuming it has failed and they have soaked up water (would they really soak up enough water to darken the entire tile?), will they dry out and return to their normal shade if the seal is made good or is it a case of taking them all off and replacing them?

:icon9:

 

[Dan]

Hi, replied to your thread in the pro's room. But i think this is a case of the tanking system stopping the water from getting out through the last row of tiles and after a long period of time, it's eventually just sitting in the back of the tile soaking in the biscuit. If you remove the seal at the bottom, maybe silicone or whatever. Then re-seal with a sealer strip that can let the last row of tiles breathe, you should find they will change back to the original colour once they have dried out a bit.