hi guys and girls, I have today been and looked at a tiling job that has been done by another tiler for a builder!
The tiling work is very good indeed, but there is a problem with the grout, and the builder asked me to have a look for a second opinion! but im a bit baffled so wondered if you might have any ideas???

The grout is grey and has gone black in small areas and not all over and in different areas with different substrates as follows!

The adhesive used in all situations was everbuild rapid set flexible grey and and everbuild flexible grey grout! Both are suitable for interior and exterior areas!

out side area !
This is a sand and cement screed which was sealed with pva as directed and specked by everbuild and there adhesive and grout, tiles are slate and the tiles and grout was sealed with 2x coats of stoneglow sealer!
The grout has gone black patchy and it is very soft where it is black but the areas that havent gone black are hard and fine!

inside area Kitchen and conservatory!
this is a pored screed anhydrate according to the builder with wet ufh specked by everbuild to seal the floor with there pva However the builder did say that the tiler used a sealer from mapei called primer G! 2 coats were applied and then tiled with the same adhesive and grout the tiles are the same as the ones out side slate! and the tiles and grout was sealed with 2x coats of stoneglow sealer!
And these are fine have not changed in colour atall!!!

Inside area utility and hallway floor!!
this is a pored screed anhydrate according to the builder with wet ufh specked by everbuild to seal the floor with there pva However the builder did say that the tiler used a sealer from mapei called primer G! 2 coats were applied and then tiled with the same adhesive and grout the tiles are porcelain!
The grout has gone black in patches again not all over the rest of it is fine! there has not been any sealer applied to these tiles or grout!!

indoor pool area!
This is a sand and cement screed with wet ufh same primed with mapei primer G again adhesive and grout used with the same porcelain tile and with no sealer applied to the tile or grout!
And this area has not been affected at all!!

I did tell the builder that everbuild would not have been my choice for the adhesive and grout, and he said thats what the tiler said and the builder supplied the materials, The tiler who did it has been back to look and told the builder I told you not to use everbuild you supplied the materials and he suggested to get everbuild to come and have a look!
Everbuild did have a look and they diddnt know what had caused the problem and agreed to supply new grout!Goodwill gesture me thinks!! However the builder is now not useing there products again..

I thought that it could be the adhesive bleeding threw but then that doesent explain why it is soft where it has gone black? and the builder said the tiler was very clean and cleaned his joints as he went!!

the tiler who tiled it wont except responsibility and neither will everbuild,
the builder has asked if i would re grout it, but if there is an underlying problem and its not just the grout then i dont want to get involved incase it happens again!!


Here are some pictures of the grout on a poured floor with porcelain tiles!!

Any ideas what it could be!!!

I don't know what the patches are on the tiles - they look like shadows or wet duck footprints!
My best shot would be adhesive on the side of the joint/bad mix of grout/something in a cleaning agent/something spilt!
It could be coming up from below - but without removing a tile!!!
Problem is will the new grout be any better.
Will it be the same colour.
Will you have to cut out all the grout and redo it all.
Will you damage any tiles in the grout removal.
PM - Enduro - tile cleaning is his field!

Originally Posted by timeless john

I don't know what the patches are on the tiles - they look like shadows or wet duck footprints!
My best shot would be adhesive on the side of the joint/bad mix of grout/something in a cleaning agent/something spilt!
It could be coming up from below - but without removing a tile!!!
Problem is will the new grout be any better.
Will it be the same colour.
Will you have to cut out all the grout and redo it all.
Will you damage any tiles in the grout removal.
PM - Enduro - tile cleaning is his field!

the shadows was caused by me not stains on the tiles lol
thats the thing if i was to re-grout it would it happen again? i was wondering if there was an under lying problem? that cant be seen?

pool area not affected because a pool finisher did tiling

Originally Posted by gooner59

pool area not affected because a pool finisher did tiling

but no it was the same tiler, just cant get me head round it why some areas it has affected and not others as it has and hasnt happened on the same substrates which was all treated the same way..
oh and they have put a damp meter on it on the inside and it is dry! obviously wet on the out side what with all the wet weather lol

From your story I can't see that the tiler has done anything wrong and I like him would be pointing the finger at Everbuild... Don't suppose you could get Everbuild to check the batch number and tell you how long ago the grout was made. If it is dry but patchy it seems the pigment has bundled into localised areas. I have seen grout do this in old bags that have been on my shelf for 3 years, never used it but I could well have imagined it might to do something similar if I had.

Just a guess

hi peckers could be grout as mentioned by color republic my gues is its deeper than that were tiles solid in patchey areas tap around and at a gues water puddles in affected areas id say its the pva breaking down causing a mould under tiles let us know how it goes

Just had another look at this, I didn't realise that the job was an old one. I thought it had just been done. So I doubt if my other post has anything to do with it now.

How much of the patchy grout have you tried to scrape out, if any? What i'm getting at is does it run all the way through or just on the top?

Also all the pictures show the patches running in the same direction (even though you have taken pictures from different angles). So it shows it has only gone patchy on the long runs of grout not the short brick bond lines. Is this the case or does it just happen to be the photos you took?

Originally Posted by Colour Republic

Also all the pictures show the patches running in the same direction (even though you have taken pictures from different angles). So it shows it has only gone patchy on the long runs of grout not the short brick bond lines. Is this the case or does it just happen to be the photos you took?

The job is only 6 months old at the longest and the patchy bits in the grout is in the short grout joints as well as the long ones that just happend to be the pics i took! the pics are of the porcelain tiles that are inside and it is only affected the tiles that are layed on the poored floor! the same tiles are laid in the pool room but this is on sand cement screed and they have not been affected atall

but it has happened to the slate tiles that are outside and they are on a sand cement screed

but it hasnt happened to the slate that is inside that is on a poured floor!

this is really weird

could there be rising damp from underneath?

See something like this before. Turned out there was a leeking pipe that was burst between the tiles and substrate. so water was runing along under the tiles and god knows how but disscoulering the grout from beneth.

any spare tiles on the job? try lifting a couple and inspeact whats happening underneath

it sounds like bad batch of grout to me, just because some rooms are patch free and some aren't. I'm guessing that the tiler grouted one room/area at a time, using different bags in each room/area

what size joint is it ?

2mm by the looks of it, why what you thinking Gary? Shed some light

does the customer have dogs? looks to me like they have been peeing on the floors and it has got under the tile just a guess but the only time i have seen any thing like this sort of thing before is in a house where the dogs were peeing,I am guessing they stay in the utility and go into the outside area for a leak

good thinking Gary

That could well be IT!!! I remember years ago we did a kitchen up after a fire, we laid the floor and six months later a similar thing happened, when we took the floor up the smell of urine made us gag and the Alsatian had a guilty look on his face. The woman was not happy because we made her pay for re-doing it as it wasn't our fault. Funny thing is we always suspected that the fire was started on purpose for an insurance job, payback some would say

Regardless of the whys and wherefores of how the grout is patchy and discoloured, Aquamix Grout Colourant is your easy answer in terms of a solution.

I was asked to look at something similar in a conservatory recently. I simply re-coloured it for them and it looked fantastic afterwards.

Originally Posted by Doozy

Regardless of the whys and wherefores of how the grout is patchy and discoloured, Aquamix Grout Colourant is your easy answer in terms of a solution.

I was asked to look at something similar in a conservatory recently. I simply re-coloured it for them and it looked fantastic afterwards.

but the grout is soft where it's patchy Doozy, AM Colourant won't sort that out

Originally Posted by doug boardley

but the grout is soft where it's patchy Doozy, AM Colourant won't sort that out

I do apologise I missed that bit.

Still, replace the 'soft' areas with a similar grout, then re-colour the whole area for uniformity of colour.

reminding us that the grout was soft puts down the pee pee idea. surely dog wee wont soften the grout?

Originally Posted by Prem Tiler

reminding us that the grout was soft puts down the pee pee idea. surely dog wee wont soften the grout?

dog pee would soften the grout, it can be very acidic

thanks for your thoughts and replys, but the house is empty the owners havent moved in yet and there is no dogs there, good thought but unfortunatly not the answer..
I did wonder if it was a leaky under floor wet heating system that had a leak in the indoor area but the pressure has not dropped in the heating system! have seen this before and it did discolour the grout but it wasnt soft! but it has also happend to the outside areas and there is no wet ufh there! although i did wonder if water was getting trapped under the tiles in different areas?
I have spoken to the builder again and he has said that before it went dark it went white with like salt deposits on the top and it has since gone black!
the grout joint inside on the porcelain tiles are 2mm and on the slate it is 4mm.

I am at a loss as to what is or has caused the problem!