Right now we’re receiving a fair bit of email relating to the cloudy haze and appearance of porcelain tiles, especially those sourced from countries like China. Here’s one of the latest:

Question: “We have had porcelain tiles laid and there is a very distinctive cloudy appearance all over the tiles. We have tried many tile shops and tried their residue removers but with no luck. We have had a tile company come and look at our tiles and tried their solution but still no luck. We’re beginning to wonder if the tiles are faulty as we purchased them from a Chinese warehouse.  Please can you help as very disappointed with them?”

Our Answer: “Hi, sorry to say that this sounds like yet another example of what is
becoming a classic problem with imported modern porcelain from certain sources. The distinctive cloudy appearance you report, is most like a grout haze.

This type of porcelain tile can have many microscopic holes (like tiny gas
bubbles – think of the holes in a loaf of bread) in the body. The polishing process removes a fine layer of the tile’s surface, just as using sand paper on wood does. This process can take the tops off some of those holes, thus exposing them, we cannot see them too easily as they are so small.

However, the grout is smeared all over the surface and some of the liquid containing cement, water, polymers and pigments) can be forced into these holes any sand in the grout would be too big). When the tiles are washed to remove the surplus grout, it can be very difficult to remove the coloured ‘grout water’ from those tiny holes.

So, it remains there and is allowed to dry. There are so many of them that when you look at the tile they all appear to merge into one – like pixels in a TV image giving an all-over cloudy or hazy appearance.

These tiles would have benefited from sealing prior to grouting but there are a number of things you can try. Given that you have tried several cleaners already, I am going to  assume you have tried a proprietary grout haze remover (acid based) so I would try one other thing, before moving on to a last-chance, combination approach.

First I would try MicroscrubTM, this is a micro-abrasive cream cleaner. The abrasive is derived from calcite and is soft enough so as not to damage the tiles, but it might just provide enough gentle abrasion to remove some of the grout. It also contains nanotechnology which simply means it can get into some of the micro pores – so worth a try.

If that fails, go for the combined approach:

First apply a solvent based stripper, neat spread over the affected area and leave for 30 to 40 minutes, Then, without removing the solvent, now add to the floor, some diluted grout  haze/cement cleaner, (make sure it is based on phosphoric acid or similar and not HCL), leave the two chemicals for another few minutes (the first product is attempting to break down any polymers present, this takes time, once it has done this there is more chance that an acid can now work on any cement present).

At this point, add some MicroscrubTM – just a couple of blobs, mix it into the solution and leave again for a few more minutes (the nano particles in the product help to allow the chemicals to ‘go deeper’). Don’t worry about the acid wanting to react with the calcium in the MicroscrubTM, by now the acid cleaner will be mostly spent, and it’s job done (this is why we wait until the end to add the MicroscrubTM). Now scrub, with a white nylon pad and really try to work the mixture into the tile. Clean up the slurry and rinse well with clean water.

I hope this improves the situation, more often than not it does, but there are some situations that cannot be saved; sometimes it is not so much the grout haze, but a waxy coating (a very stubborn one) that gives this appearance (the above procedure may well help with that anyway). Other times there can be a polishing fault in the tile, in that the tile has not been correctly finished at the factory – this cannot easily be rectified.

I hope this has been helpful. If you have no joy, perhaps you could send us a picture?

Copyright Ian Taylor and The Tile and Stone Blog.co.uk, 2013. See copyright notice above.