HELP I need Help removing cured grout too [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


View Full Version : HELP I need Help removing cured grout too

09-17-2001, 10:33 AM
I have jsut read the thread from the person who needed help removing grout from her tiles. Vinegar might have worked for her but I think my problem is more serious.
I've just had a friend of a friend (never hire these people) install ceramic tile in my kitchen. The tile is a single fired rough texture. The guy left the grout on the tile too long and now there is cured grout on my tile that has settled in pin head size pockets and along the ridges of the tile. I have tried a lot of elbow grease and AJAX, HG Extra Cleaner and Mecuric Acid (I think that is what it is called). None of them work perfectly, when the tile is wet, the charcoal grout turns black and shows on the tile. Any suggestions (for the floor, not the tile guy, I have that one figured out)???????

Sponsored Links

09-17-2001, 12:00 PM
It sounds like you've tried everything...hopefully the little pinholes have glaze inside them...that would make it a little easier to clean. You may want to try a nylon scrub pad or a stiff nylon brush the next time you give it a acid wash..unfortunatly, the more times you use acid, the more you weaken the grout joint...though I don't think you have a choice right now.


John Bridge
09-17-2001, 03:24 PM
I think you mean muriatic acid (swiming pool acid?), and as Brian has said, you need to protect the grout joints, or you'll weaken them. You can do this by soaking the joints with water before you use the acid. The water will inhibit the acid from penetrating into the joints.

When using a brush you must cover your eyes with goggles. Also, don't inhale the fumes. Dilute the acid to about 1 to 4 with water. I think you already know about the rubber gloves.

It's a slow go, but a tooth brush might be helpful.

It's very possible you will have to live with at least some of the grout.

09-17-2001, 03:33 PM
Thanks Brian and John
Any advise on the strength of acid to use. I tried 3:1 and it didn't help much - think I can go 2:1?

John Bridge
09-17-2001, 04:36 PM
I said 1 to 4, and that's really strong! If that won't do it, nothing will.

You can try dislodging pockets of grout with a hardwood dowel and a hammer. I'm not optomistic about this. Sorry. :(

Rob Z
09-17-2001, 05:31 PM

Could you tell use what the brand of grout is? Did the installer add a liquid latex additive, or does the bag of grout say "Polymer modified, just add water"?

If he used a concentrated latex additive, you may need to use a stripper that dissolves the latex film.

Let us know what the products were that were used.


09-18-2001, 08:19 AM
it was a polymer modified type grout - just add water

Rob Z
09-18-2001, 04:02 PM

I'm at a loss then. I haven't ever had a grout removal problem like this. Any stubborn grout hazes I have had came off with sulphamic acid.

Are you letting the acid solution sit on the tile for a minute so it can do some dissolving?


John Bridge
09-18-2001, 04:12 PM
I think we're talking about a serious buildup here. Is it possible for you to either post a picture or email me one to post so we can see what we're up against?

09-19-2001, 08:43 AM
Te buildup is more then just a haze - it is hardened grout in the small ridges and grooves of the tile, in some spots it is like specks of dark grout.
Last night I tried the HG Extra cleaner again (this is a phosphoric acid base) and it seemed to work better at full strength if I left it on for about 15 minutes and sponged it over the tile periodically.
I have not tried sulpharnic acid - is this worth a shot?
With the muriatic acid I used a 1:3 mixture but I didn't leave it on for a minute - I was afraid it would damage the tile. I could try it again (in an inconspicuous spot)and leave it on a minute before removing.

I'll check around for a digital camera and try to get a picture.

John Bridge
09-19-2001, 04:31 PM
1:3 is too strong for the muriatic. Maximum 1:4. And soak the grout joints before you apply it. This will keep it from penetrating too deeply and eating up your joints and your adhesive.

Please be careful. Don't inhale the stuff.

09-20-2001, 09:19 AM
I tried the muriatic acid again, about 1:4 and guess what it worked - woo hoo. I left it on for a few seconds longer this time and then used a brush to scrub it off. Looks good and not too slow a process.
My only worry now is if my grout gets discoloured from the acid or other cleaners that I used (I am soaking the grout with water now before applying the acid), but I think I can paint the grout if need be.
Thanks for all the advise.

John Bridge
09-20-2001, 04:25 PM
I am truly happy we didn't have a major screw up here. Yes, if push comes to shove, you can use a grout colorant on the joints.