Matte black porcelain grout haze

[Sean Kelly]

I’m sure you have all come across matte black porcelain tiles that look like slate.

I was careful when laying them. Any adhesive that got onto the surface of the tile was cleaned off and the tile cleaned up ok.

Grouting with grey superflex my troubles started. You know that I’m going to say ‘Grout Haze’, and you would be correct. In the end I had to leave the job. I’m going back this week to give the floor a good clean.

What do you do with these types of tile that retain the grout? Do you wipe down after grouting, but come back another day to clean? I’m just paranoid about over washing and causing efflorescence.

Speaking of efflorescence, I used ditra and found that it took longer for the adhesive to set. Is this normal? I also found that when I washed the floor prior to grouting I found a couple of wet patches where the water had pooled in between the grout lines. This caused three 2inch lines of white (efflorescence) grout on the kitchen floor. I told the customer what it was and that I would rake it up and redo them. He said he could live with it!

 

[Alan.P]

Sounds like your cleaning off to quick, and why would you wash the floor first ? that will only lead to problems of over watered grout, it may not look like much but it does make a big difference, and floods the open grout lines, as you say.

 

[Sean Kelly]

I actually waited about half an hour Alan before washing off. Very good point about cleaning tiles before grouting. It was only a slightly damp microfibre, but I guess a few drops of water got into the joints somehow. I know I can't seal these tiles before grouting, but I've been caught out before with this type of tile.