How can you repair cracked grout on newly installed tiles?

Question

Not long after a newly installed tile floor was put in, the grout started to crack in many places (all on same side of floor). It's a mess and we don't know how to repair it so it doesn't happen again. HELP!

Answer 1

Uh oh. You need to provide some more detail, but my suspicion is the tile is loose. It could be a variety of reasons. Structural-there is an excessive amount of deflection, but that shows up as cracked tile, too. Improper substrate-if the tile was installed over plywood or other underlayment, the mortar used to set did not cure properly and did not bond to the substrate. Weather-mortar can freeze. In new construction, not remodel, this can happen next to doors, but usually doing very cold (teens and lower) conditions. Improper mixing or spreading of mortar-if the mortar is too thin or too thick, it won't bond to the tile or the floor. Too thick it won't bond to the tile, too thin it won't bond to the floor. If it wasn't spread correctly, with proper trowel or too thin, then it won't work.

To see if the tile is loose, simply tap on the tile with knuckles, like knocking on the door. You can hear the difference, loose will sound hollow, secure will sound, well, solid.

Very rarely, I've seen cracked grout due to the actual grouting, but it is possible, if it was not mixed right, or spread right. Too thin it will be soft, and will easily break out. Another possibility is dust and debris not removed before grouting. I've seen that one time. The contractor simply grouted over sawdust that was packed in the tile. They set the tile, did the trim work, painted the house and THEN grouted without vacuuming the sawdust up. It was a mess.

If you hired someone to do the work maybe you should get an independent third party to look at the job, but you have a bit of a mess.

Answer 2

There are many questions to ask first. How old is the building? Is it still settling? If so: wait until it is done moving before repairing, or you will just end up doing it again. Was the tile installed over cement board, plywood, or what? Each has a different effect. Did you use mastic or latex/polymer modified adhesive or..what.. to adhere it? Is this a wet area application (shower, counter top, etc?). This could be as simple as having too much water in the grout when it was mixed, or too wet of a sponge during clean up. If that is the case, you still have to remove it all and redo it. Just fact-find to learn the cause before you repair it, so you only have to do the repair once! Ultimately, if you paid someone else to do the job, have them fix it. If you did it yourself, go to the library and read every tile book you can find. The answers are out there, but it might take some research to find them.

Answer 3

Did you do the floor yourself or have it done. I would call the comp that did it and have them fix it. If they didn't mix the grout right then it will crack. Or if you want to do it your self, you can buy more grout at a hardware store, make sure you get the matching color, all you do is add water, it tells you how much on the bag. Then get a rubber spatula-(also at hardware store) and mix the grout, then lay it in the cracks and use the spatula to level it in the cracks. It will wipe off the tile with a wet wash-cloth. Then you also buff the tile with a soft dry cloth. You can also get an instruction manual at the hardware store that will tell you in more detail how to do it. Try Lowe's or Home Depot, they are really help-full.

Answer 4

I used to work with tile , I think that the problem was too much or too little water in the grout , so i would try to peel off as much bad grout as you can ( You can put water on top of the bad grout and with a sandpaper peel it off) and then put good on top of it. The ideal grout texture is like toothpaste.
Good Luck.