Hi guys

Anyone got any idea why bal charcoal grout in porcelain mosaic on walls is discolouring.ie:

some of the grout is almost black and other parts are quite grey in appearance

this is happenning on a job i am working on now so far i have only grouted some of the job.

my suspicion is it is because the area in which i am working is very damp.

Any thoughts

Is this happening as it is drying after grouting..?

Efflorescence??

Is the area where the problem is, damp while you are grouting or after you have grouted ?

D,
This may be as a result of adhesive in the joints "killing" the grout, what make of grout is it????? Dont say mapie please.
Paul

read again paul..he does say which..

Bal Paul

OOPs, thats what you get when you are reading and fighting off 5 year old twins, any how back to topic.
D does this effect go when you wet the grey areas? if so I would let it dry out completely and take a fresh view, as I say if the adhesive is present in the joints close to the surface of the tile/mosaic it can cause this.
Paul the deslex dislex bad reader

Hi all
Yes the area is damp it is toilets in a restaraunt in a basement in london.There has been a problem with water leaking in although not in the actual area in which we are tiling the tiling is all on new stud walls.This weekend just gone the whole basement flooded they have sorted the leek now but the water was 6 inches deep on sunday.But the problem started before the flood.

Discolouring started the day after grouting and is getting more patchy by the day i still have about 30 mtrs to tile and grout and dont want loads of problems.

I had a similar problem with bal charcoal a couple of years ago where the grout actualy got like a blue film over it and bal said it was due to cold conditions drawing out the Efflorescence.But this is not a blue film it just looks like some of the grout is drying a lighter colour.but i suppose it could be the Efflorescence.anyone suggest a product to get it right without to much work because im on a tight budget for this job.ie:Efflorescence remover.

obviously i Cant change grout half way through.

Surprised they even tiled in such a short time with that amount of flooding

I'm having the same problem with Mapei black. Mixed it much drier than usual too, in the hope of avoiding efflorescence!?!

Too many fixers put shading down to efflorescence....This can be a number of things from incorrect mixing and over wetting when washing off and diluting pigments...before washing off you are supposed to let a grout set up firm and if you wash too early then shading can happen...also if you over wash this can draw the polymers to the surface..this can cause the lightening effect on the grout some fixers experiance...

Effloresence is salts from portland based products..i'e adhesives /grouts etc and is a white powdery substance...not shading in grouts and blue like effects..that is polymer or diluted pigmants from over wetting when washing off.

Mapei ultra colour is actually an anti efflorescence grout...

Ultra colour plus : Fast setting and drying, high performance, anti-efflorescence grout, polymer modified, for joints from 2 to 20 mm. Water-repellent with DropEffect® and antimold with BioBlock® technology.

Hope this helps fixers know why shading can happen..

Also here is some info on what effloresence is and the causes and cure...

What is Efflorescence.pdf (application/pdf Object)

its probably too much water when first cleaning the joints also with charcoal and ebony grouts its important to get the mix right

Originally Posted by Dave

before washing off you are supposed to let a grout set up firm and if you wash too early then shading can happen...also if you over wash this can draw the polymers to the surface..this can cause the lightening effect on the grout some fixers experiance...

I generally let it firm up to the point where it takes a bit of elbow greese to profile it with the washboy in a circular motion, then when the tiles are powdery and dry to the touch i wipe in straight lines with clean washboy sponge which is as wrung out as i can get it.

Is it possible i'm letting it firm up too much the 1st time, and in doing so, squeezing too much water from the sponge while scrubbing? I dunno!?!

Also, when you say about the salt deposits (which is what i thought i was getting) being powdery... Should they just scrape off with your nail? Just curious, as on some occasions it seems to scrape off (not permanently), but in this case it isn't.

And on another note.... I remember someone telling me about using Aquamix Colourant on patchy grout. Would this solve this particular problem, if it is down to over wetting?

I had this problem a few years back with the same grout ! I sorted it by mixing absolute correct quantities (water/powder) as per instructions instead of just thinking that looks about right, you live and learn !! So if your along the same lines try mixing it by the book as it were see if that helps

I tried mixing a 2kg bag as per instructions, and it was way too wet!?! I remember reading that some of the mapei bags had the wrong instructions on them, but no idea if that was the 2kg bags!?!

The modern flexible grouts today made by all top manufacturers are made to very high standards. They are continuously tested in Lab conditions to get the polymers bang on for maximum flexibility. It is extremely important to follow the manufacturers mixing instructions to the letter then let the grout rest and then slake it again prior to using. The days of guessing how much water ? That looks right are over! Invest 79p in Asda or similar for a 2 litre plastic mixing jug and get it right the first time is my advice.

tel

Originally Posted by Terry Cottar

The modern flexible grouts today made by all top manufacturers are made to very high standards. They are continuously tested in Lab conditions to get the polymers bang on for maximum flexibility. It is extremely important to follow the manufacturers mixing instructions to the letter then let the grout rest and then slake it again prior to using. The days of guessing how much water ? That looks right are over! Invest 79p in Asda or similar for a 2 litre plastic mixing jug and get it right the first time is my advice.

tel

I pinched the one out the house.....she was best impressed
..

Originally Posted by Terry Cottar

The modern flexible grouts today made by all top manufacturers are made to very high standards. They are continuously tested in Lab conditions to get the polymers bang on for maximum flexibility. It is extremely important to follow the manufacturers mixing instructions to the letter then let the grout rest and then slake it again prior to using. The days of guessing how much water ? That looks right are over! Invest 79p in Asda or similar for a 2 litre plastic mixing jug and get it right the first time is my advice.

tel

That's great if you're mixing full bags, (although as i said above, on the 2kg bag i followed the instructions to the letter (with measuring jug)), but if you're mixing part bags, you then have to use scales too, and that's a pain in the arse!

Probably gonna have to invest in some scales at some point, but would rather just use the aquamix colourant if that rectifies the problem.

Originally Posted by beanz

That's great if you're mixing full bags, (although as i said above, on the 2kg bag i followed the instructions to the letter (with measuring jug)), but if you're mixing part bags, you then have to use scales too, and that's a pain in the arse!

Probably gonna have to invest in some scales at some point, but would rather just use the aquamix colourant if that rectifies the problem.

Just mix up full bags then or spend a few quid on a kitchen scale for site. Or do the sensible thing the night before you are going to grout and measure your grout out into 1 kg bags. Me personally I just charged for whatever grout I thought I was going to need and left the excess with the customer. Couldn't be ar**d to carry opened bags of anything in my van. My opinion was they would either go hard, out of date or spill so I never bothered.

tel

hehe! It's not really about carrying part bags for me, I just can't grout quick enough to warrant mixing a full bag.

Looks like i'm gonna have to suck it up and buy some scales lol!

Hi just to update

The rest has now been grout now the job is dry and no more problem. the patchy areas have been cleaned with Effloresence remover and is ok now.

Dave the blue effect that i mentioned is the salts sitting on top of the dark grout and makes it look like it has a blue tint.

Originally Posted by derekg

Hi just to update

The rest has now been grout now the job is dry and no more problem. the patchy areas have been cleaned with Effloresence remover and is ok now.

Dave the blue effect that i mentioned is the salts sitting on top of the dark grout and makes it look like it has a blue tint.

What efflorescence remover did you use?

tel

Found the same thing happening on a hotle i tiled wasnt damp or anything just changed to mapie black grout soon fixed the problem