Grout pen or re-grout, black grout which has turned white?

[frusc]

Been going around rectifying problems left since refurbishing my house and would appreciate some advice on this issue.

In 3 bathroom/wc's and a porch we have used Bal Superflex black grout on the floor. Just days after grouting the grout started to turn powdery white. It looks like a chalky substance is rising up through the grout.

All four areas were done at separate times and the grouting was done a few days after the tiles were laid. A different tiler did the porch area. And a new bag of the grout was used for that.

In one area there was a loose tile that caused the grout around it to crack and the exposed area has the original black colour I was expecting.

The advice I have been given to date is to either use a grout pen or use a grout saw and re-grout. Ideally I would like to do the job properly and go with the second option. But I'm concerned if I don't determine the cause of the problem first, the result will be the same

We have very hard water (I know from how often I have to de-scale my coffee machine), could that be a cause? As I could use distilled water instead. Alternatively I am considering trying to scrub a layer of the top to see how deep the white discolouring penetrates (i.e. if the cracked area is indicative of the whole lot).

 

[mypetearthling]

I could be wrong, as I don't know if Bal superflex is susceptible but it sounds to me like you have efflorescence. If this is the case, you'll be able to take the top layer of grout off by using a mild acid, such as Lithofin cement away (diluted) try it on a small out of the way area first and avoid use on most natural stones.


K

 

[frusc]

I could be wrong, as I don't know if Bal superflex is susceptible but it sounds to me like you have efflorescence. If this is the case, you'll be able to take the top layer of grout off by using a mild acid, such as Lithofin cement away (diluted) try it on a small out of the way area first and avoid use on most natural stones.


K

I've got some cement away at my parents place. Used it to remove a type of cement which was used to bond components, unfortunately I forgot about one batch and it destroyed the components swell .

Most of the tiles are Porcelain, so if it works I shouldn't have a problems using it on those. Only one of the shower cubicles has a natural pebble mosaic. Is there an alternative for this? A wire brush?

Thanks for the very quick reply

 

[mypetearthling]

Do you have any bits of the mosaic left over? You may be able to test it on that. It does say that it can be used on some stone, but I'd be careful!
Is the mosaic sealed in any way?


K

 

[frusc]

Do you have any bits of the mosaic left over? You may be able to test it on that. It does say that it can be used on some stone, but I'd be careful!
Is the mosaic sealed in any way?


K

I think I have some left with the spare tiles, so I will give it a shot. Its not sealed yet as I wanted to figure out the problem with the grout first. It's basically pebbles on mesh, grouted over.

This does remind me of one thing I forgot to mention. When the grout is wet, it turns black. As soon as it dries the problem returns.

 

[mypetearthling]

its just the salts in the grout rising to the surface. The usual cause is the tiler using too wet a sponge when cleaning the grout back. with your mosaic, has the grout stained it at all? the normal advice with that sort of product is to seal before laying as it makes them easier to clean afterwards. Are your something like these?
http://www.originalstyle.com/tile_mosaics_stone_pebble.htm


K

 

[frusc]

its just the salts in the grout rising to the surface. The usual cause is the tiler using too wet a sponge when cleaning the grout back. with your mosaic, has the grout stained it at all? the normal advice with that sort of product is to seal before laying as it makes them easier to clean afterwards. Are your something like these?
http://www.originalstyle.com/tile_mosaics_stone_pebble.htm


K

They are similar to those, but mine came with the stones on a mesh, nothing else. Not sure if the pictures there are supposed to show them after grouting, or they come like that.

The grout did coat the pebbles aswell and the tiler foolishly didn't wipe them straight away. He ended up having to do some scrubbing with some grout remover to get it off all the stones Luckily they look fine now.

 

[frusc]

http://www.youtube.com/watch?v=EXrQrGXs6Fs

They were like these, although they look better

 

[frusc]

Finally picked up the cement away and did some test patches. Looks like its worked, including not damaging the pebble mosaic.

Thanks a lot mate, really saved me a lot of trouble.

 

[mypetearthling]

Glad it worked... much easier than re-grouting!!


K

 

[frusc]

After my last post I spent a few hours applying the cement away to all the affected areas. Unfortunately the results were not as good. While large parts responded in the same way as the test patches, in other areas the white patches remained.

Having repeated the procedure in those areas, it became apparent it was not going to work. So I gave BAL a call and was put through to one of their local reps.

His response was that he suspected efflorescence and could only surmise I was unfortunate that both tilers either made a mistake when grouting or they did everything correctly and it still appeared. None the less he said his first advice would have been to use the cement away aswell. He suspected the areas that didn't respond were infact where the salts had gathered for some reason and the efflorescence penetrated much deeper in to the grout.

He suggested I try a trick he used, which was to use a small brush to apply linseed oil to the grout lines. As he suggested this appears to have resolved the issue for now. He did say to apply a test patch first, as the this can make the grout a little shiny, but this doesn't seem to be the case for me. The only downside so far was the effort in applying it to the lines and cleaning the excess off the tiles and the smell which lasted a few days.

I'm crossing my fingers this lasts, as otherwise I will have to bite the bullet and re-grout. Quite probably using another brand

 

[TileandStoneBlog1]

Hi Frusc,

This is a very common problem, and it is not unique to just one grout manufacturer - every one of them has the same issues as it is a naturally occuring phenomenom with the cement they all use. There are some new 'efflorescence-free' grouts that are supposed to have solved this problem by using a different type of chemistry - but the jury is still out on this.

So I guess what I am saying is that even regrouting, with all the mess, time and risk of damage to tiles, will not be guaranteed to prevent this from re-occuring, whichever brand you use.

Also, the acid cleaner you used is a bit too strong for my liking, as (to my knowledge) it is based on HCL - hydrochloric acid. The fumes alone from this can affect anything metal - so be careful using it anywhere near metal fittings.

The acid in it will attack and dissolve any of the efflorescence (salts) that it comes into contact with, more or less instantly, but there are three other issues: 1 is that the acid-cement reaction will create more 'salts' of it's own; 2, the acid reaction, will etch the grout, this means it will burn away some of the finer particles of cement, leaving the surface of the grout microscopically altered, less smooth if you like, as it has 'pulled' finer particles out of the surface - this is not visible to the eye, but it's effect on light is - the 'rougher' surface now scatters light at more angles and the result is a bleached effect - making the grout appear lighter in colour (so you get rid of some of the efflorescence, but replace it with a salt by-product, and effectively bleach the colour at the same time - plus the acid can pull some of the black pigment out too). The 3rd issue is the water used with the acid will possibly spark off a new instance of efflorescence in any case - I have seen many jobs cleaned with acid, look great and 2 days later when they have dried, it is back, or rather there is fresh efflorescence.

As for the olive oil, this is a good test or indicator that an enhancing sealer may work (simply to mask the problem, what it is doing is altering the way light is reflected, same as wetting the joint with water, only that only lasts as long as the water). Ultimately the oil will fade quite quickly and can go to look dirty.

I would investigate using a more mild acid, based on something like phosphoric acid, very dilute and limit the amount of water used (you have to use some, for rinsing after) - dry the tiles and joints down after rinsing, get some warm air moving, get that moisture out fast.

Then consider either an enhancing sealer (will do what the oil did but much more permanently) or a grout colorant (a epoxy-modified coating that can be applied topically to existing grout, completely restore/renews the colour and seals the grout at the same time)

Hope this helps

Ian