discolouration with grey grout?

[tactile]

i'm having trouble getting an even colour through the grey grout in a bathroom i tiled a few month ago.

I tiled a bathroom about 7 weeks ago. Newly plastered walls which had been dried out for at least 4 weeks. I primered the walls with proper tilers primer and left to dry. I used ready mix BAL tubs on the walls as normal, and flexi cement on the floor. I then used Ultra grey flexi wall and floor grout throughout. I have done everything as I usually would (been tiling 5 yrs and no call backs to jobs), but the grout dried all patchy. Dark Grey in places, light in others, I've since raked out 2-3mm of the grout throughout the bathroom and regrouted using a dunlop (BAL) grout, and the same thing has happened! . . . any ideas?

When i raked out the first lot of grout, it seemed totally dry throughout the layer, so it was all properly set.

One of the technical helplines has recomended Universeal grout restorer as it could be a problem with the walls? . . anyone used this product?

[Bri]

You say the grout was ultra, is that ultra colour plus from Mapei?

[tactile]

No, the actual firm is called Ultra! . . . I know, it aint popular!

[Bri]

I've not used their grouts or adhesives but do use the SLC loads. There have been quite a few similar threads on here recently with the same problem you have, I've also had the same problem myself. The universeal is a good product and is what I used to fix my own issue. I don't want to bad mouth any specific manufacturers but, I've stopped using 2 brands of grout as the customer service I received in relation to the problems was truly awful, the tiler is to blame was the general answer. BAL grouts are the only ones I will use from now on as I know they perform and give a consistent colour without having to get a measuring jug and a set of scales out to mix the grout.

[Dave]

What size tile was it and how deep/thick did you use the adhesive..?

[tactile]

It was a 60x30 tile and i did use ready mix tub. I know a lot of tilers say thats a big no no, but i've done it for 5 years and i know alot who do. I've never had any problem in the past and i dont think this is the issue. There is always the argument that there will be moisture trapped behind etc, But it seemed pretty much dried out to me.

[tactile]

I've not used their grouts or adhesives but do use the SLC loads. There have been quite a few similar threads on here recently with the same problem you have, I've also had the same problem myself. The universeal is a good product and is what I used to fix my own issue. I don't want to bad mouth any specific manufacturers but, I've stopped using 2 brands of grout as the customer service I received in relation to the problems was truly awful, the tiler is to blame was the general answer. BAL grouts are the only ones I will use from now on as I know they perform and give a consistent colour without having to get a measuring jug and a set of scales out to mix the grout.

So this universeal grout restorer is good?. . . thats a relief, i'll be glad when this one is sorted. The technical helpline said there has been loads of problems recently, its all the crap they put in the grout these days, polymers etc.

[tactile]

Is Aqua mix just as good?

[Dave]

It was a 60x30 tile and i did use ready mix tub. I know a lot of tilers say thats a big no no, but i've done it for 5 years and i know alot who do. I've never had any problem in the past and i dont think this is the issue. There is always the argument that there will be moisture trapped behind etc, But it seemed pretty much dried out to me.

So that makes it right then..?

30x30 is the max size with dispersion adhesive.. and if used greater than 3mm depth ,then moisture will be there and this CAN cause grout discolouration..as the moisture tries to escape.. You sealed the walls and this also prevents moisture escaping into the substrate, so the only way out is through the joints..

That is one take on it but also it might be your washing off method.. over wetting or not allowing grout to set before washing down can cause polymer leaching.. but these are worth thinking about in the future.. and just coz you have always done it with dispersion adhesive does not make it right.. so again might be worth changing your working practises to what is the correct adhesives to be using..and not just coz others you know do it..

[Bri]

Is Aqua mix just as good?

Aqua mix is good, but IMO the universeal is better.

[Sir Ramic]

Aqua mix is good, but IMO the universeal is better.

I totally agree.

[pjc]

as Dave i used to see it a lot with bal grout years ago always discolour around where peeps would pack windows to make them plum ect or where to walls were not porous even on small tiles can take weeks to dry