Concrete based grout scratching off [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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08-30-2010, 03:25 PM
I used smooth black concrete grout mix to grout a granite-tiled kitchen counter top...The grout was mixed well using water and wasn't too soupy (or so I thought but I probably should have used the additive they sell)...However, a month or so after grouting, the grout still flakes and wipes off (making the kitchen towels black). My joints are really narrow (the granite tiles nearly butted together) so I imagine I made the wrong choice in choosing the concrete/mortar based grout...should have went with the Laticrete Spectralock since my joints are shallow and narrow I am thinking.

However, cutting it all out won't be there another way to harden up that grout?? Maybe a sealer or damp curing or is it just way too late in the game for that? I realize that many would think that tiling a kitchen counter top was silly, but even amidst that, some solutions would be helpful. Thanks for your help!


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08-30-2010, 03:39 PM
too late for damp curing or to stiffen it up. If its coming out with the swipe of a rag then scrape it out, regrout it with spectralock or unsanded (mixed correctly), should be like peanut butter or a little stiffer is how I like it.

theres nothing wrong with a cement based grout if mixed and applied correctly.

Houston Remodeler
08-30-2010, 03:46 PM
Time for a re-grout. I doubt spectralock will fit in between those tiles. Can you post a pic of the grout joints with a dime laid across for size?

Use unsanded grout following these instructions (

08-30-2010, 08:32 PM
As suggested I took the advice...
1. Cut out all existing grout (not too time consuming since the space between wasn't wide and was fairly narrow and cleaned (vacuumed) thoroughly...allowed to dry (even though it wasn't that wet)
2. Using Laticrete black un-sanded grout, I placed approximately 2.75 oz of water in the mixing pail (I didn't use the whole batch since the job is small...I wonder if that contributes to my issues...maybe the mixture of portland cement is not distributed properly??) (the ratio was based on 47 oz of water per 8 lbs of mix)
3. I then added approx 8 oz of the grout mix...mixed by hand until it seemed mixed through well, then let it set for eight minutes or so...
4. It was a little glossy but seemed set well (forgot the proper term, sorry) and then I was the consistency of a smooth peanut butter...maybe peanut butter with honey since it was stiff)
5. Use the float to press in the grout and then went diagonally to wipe off excess
6. It hazed over pretty quickly (maybe my under-cabinet lighting is too hot and is offsetting the dry/cure time?) but I still waited about 20 minutes
7. Using a damp but completely drip-less sponge (not a kitchen sponge...I think I used what most profs would use) I lightly (barely any pressure) smoothed over the joints and remove some of the excess grout (at the same time being careful not to overwork the grout)
8. I did not wipe off too much excess yet as I will wait about an hour or so...
9. The tile has already been sealed (along with the old grout) so I think cleanup will be fairly easy. I hesitate to put too much water/moisture on the tile as maybe that was the issue last time?!?
10. Now I wait to hear from you all to see if I really messed it up again!...then I will get told (by my pretty confidant Heidi) to have someone else do it!!

Please comment and let me know if I did it right...The spectralock is a sanded product and I worried that the joint size may just be too small, but, I may have to go a different route. My brother-in-law mentioned that maybe the lack of depth and thinness of the joint was a problem for the grout I am using. However, lati's website stated that I was using it well within its formulated use.

Thanks so much for the quick response...hope to hear from you folks with any feedback...please excuse the bad spelling/grammar

08-30-2010, 08:36 PM
ive fit spectralock into joints that size, just mix it a little thinner.

looks good, dont even wipe it in an hour. wait till tomorrow.

wiping tomorrow is based on what I see in the pic. it looks pretty clean. you can buff it with a rag or old shirt in an hour if you notice any haze.

08-30-2010, 10:38 PM
Well, I hope it works out ok...I did end up wiping it...should have just waited...a residue still comes off when I wipe it with my that normal? I'll see how it cures in a day or so, but I am not too optimistic? Did I do something wrong? It is warm here, but, eh, it's maybe 80 degrees in the kitchen, or 75?

Thanks for the comments...I'll wait to figure out what happens!

Houston Remodeler
08-31-2010, 06:19 AM

You done good. Let it dry today and buff it out with an old towel. :tup1:

08-31-2010, 09:17 AM
When I rub my finger gently over the top of some of the joints, it will turn the fingertip gray...the harder I press the darker it gets. It seems to be similar to what occurred before...

Could it just be bad grout? Still too much moisture after gently wiping last night? Should I have damp cured the thing?

Thanks again for the feedback...any more advice is helpful!

08-31-2010, 04:31 PM
Well, I can't for the life of me figure out what I did is still wiping up with my finger and does not seem very solid...

Should I just get a brand new box of grout and try again?

Any thoughts?

Houston Remodeler
08-31-2010, 04:41 PM
One dope slap coming up.

Yes, you'll do much better with a new box of grout. Make sure it wasn't opened and returned, and is not dusty.

And read this (

08-31-2010, 04:47 PM
That is what I was concerned about. Come to think of it, it was dusty when i bought it a while back.

Thanks for advice and wish me luck...I hope this does the trick...

08-31-2010, 04:49 PM
Purchasing bad that common at all?

Houston Remodeler
08-31-2010, 04:51 PM
At the big box stores? yeah. thinset too. You'd be surprised the crap people bring back. The gals at the return desk have no clue what a good bag is supposed to look like and the knuckle heads in the tile dept just slap them back on the shelves. It reduces "shrinkage"

08-31-2010, 04:59 PM
figures...come to think of it the box was dirty when I bought it...If you do recommend a different brand let me know...otherwise I will try again.

Thanks for the time you took to answer and comment on my posts!