White Powder/Soap Stain On Black Tiles In Toilet

[Tics 0]

Hi everyone, 

I just moved in. Recently, there are white calcium stain on my toilet tiles and grout (as attached). 

The tiles are homogeneous tiles, with those"rocky", uneven surfaces. 

I've tried scrubbing, spraying water, vinegar + baking powder, but it didn't remove the stain. Once the tiles are dried, the stains show up. 

Anyone knows what is this (limescale, soap built up?) and how can I remove it? 

Thanks! 

[3Cube 9]

This is due to salt (not the salt used for cooking, food consumption, etc) / mineral impurity content in the sand (used either in the floor screed or the concrete floor. Most likely in the screed). The process of the white powder appearance is call efflorescence

https://en.wikipedia.org/wiki/Efflorescence

[3Cube 9]

As a building contractor myself, the root of the problem is the material used during building your property. Hence my professional advice is that this problem will go away by itself in time (Best case scenario 5~6 years, while worse case scenario 10~20 years). As time pass, the mineral / salt will be "push out" until it is depleted.

Every time you clean off the white powder, it will "appear" repeatedly until the mineral / salt is depleted.

It will not help if you hack off & redo the floor tiles because this problem had spread during the first time the floor was laid.

Obviously your contractor did not use the correct material for the type of works. In your case the material in question is sand.

There are basically 2 types. First is concreting sand which is clean processed sand (ie: "washed" in layman terms). Second is Plastering sand used for brick laying, plastering over brick wall, etc.

You contractor should be using concreting sand to do the floor screed in preparation to receive adhesive for the floor tiles. Floor screed is needed to create the "fall" or "gradient" so that when you shower, water will flow towards the floor trap which direct the water to ground drainage.

[Tics 0]

Ah.. I see. 

Thank you for your advice and sharing! 

[GoodVictor 0]

You can try lye for removal, it's good for breaking up all kinds of bloom and dirt. It's important to remove the lime with mild agents, without hard abrasive particles. You can also try chlorine and ammonia. Perhaps these stains can be soap residues, cause often when you wash your hands, splashes can "fly" to all sides. When I clean my bathtub, I often have to clean up these stains. Btw, now in almost all compositions you can find parabens - a dangerous preservative for sensitive skin, I try to buy paraben free soap then the skin feels better and there`s no itching!