View Full Version : grout changes color with application of water?
04-01-2010, 03:18 PM
My contractor just finished tiling and grouting the bathroom. We used ceramic glazed wall tiles (8 inches x13 inches) and corresponding floor tiles (13 inches x13 inches) from Porcelanosa with their recommended grout (color: beige 0-4, sanded for floor and finer for walls). The contractor sealed once. My concern is that once I splash water on the tile, the grout color changes to darker (such as before drying). Once the water dries, grout color changes back to lighter (dry). We are sealing two more times now and will test again. Is it normal that grout changes color when wet? I read in other places / forums that it is not. First, what's wrong and how to fix it ? Also, I noted that the appearance of wall grout is a bit sandy (or rather grainy)--such that if you scratch it with fingernail, some of it would come off. Is this typical? Second, I had planned to use similar tiles (but mosaic design with more groutlines...mosaic comes in 8 inch x13 inches tiles, uncut, just need to apply grout to get finished look) in another bathroom with a shower. Here, the change of the grout color upon wetting would be totally unacceptable. What grout type do you recommend for shower stalls? Please advise.
04-01-2010, 08:17 PM
Krista. grout changing color when wet is normal if the grout has not been properly sealed. The grout should cure for at least 3 days before applying sealer to the grout. This gives the thinset underneath the tile as well as the grout time to allow moisture to migrate out before the sealer is applied. If you have already put on one coat, be sure to read the instructions for how long to wait between applications. for most sealers it is best to get it done with multiple applications in one day. Again, check the sealer instructions. Once it is properly sealed, the grout should no longer change color.
Sounds like what you are scratching off the grout lines onthe wall is just sand that is not seated into the grout. There shouldn't be a lot of that if the grout was properly cleaned after installing. After you seal it, any peeling will stop.
04-01-2010, 09:54 PM
Thanks a lot for such quick advice! One more note, Porcelanosa rep said that it takes for grout ~28 days to really cure/solidify. Is this true? He implied that after that I guess color change would be smaller. He said nothing about sealing solving the problem. We did wait some 3-4 days before first application of sealer, and applied it again, so I hope I will not have to come back with more problems in this area. How long after application of the sealer, should the grout be sealed? Many thanks again, I am new to this and am glad to find this great resource on web:).
04-02-2010, 10:24 AM
Krista, what brand of sealer did you use? How was it applied? sounds as if it is not doing the job if the grout is still absorbing water. As soon as the carrier has dried (within a few hours of application) the grout should be sealed. It should begin to repel water, not absorb it. If it is not doing this, you are not getting it sealed.
Yes 28 days is probably right for a total cure of the grout. The manufacturers all recommend sealing after 3 days. I prefer 7-10 days myself, but who can argue with the manufacturers?
04-02-2010, 02:06 PM
Thanks for the image. I just tested the joints and they do look better, --they do not absorb water as much. Slight problem is that I see that sealing has been not entirely uniform. In some places grout soaks up water a bit more. However, they are not 100% (or 95% ;) sealed because I could not get them repell water droplets as in your image. Does this mean we should apply sealer another time? Is it typical to require several (3-4 coats)?
The sealer we used was Aqua Mix Sealer's Choice Gold (Professional). The instructions said that for new installations can be applied 48h after grouting. They suggest to apply, remove excess within 5min, let dry 30 min, then apply another coat if necessary; 2h after final coat test with water droplets. They suggest to apply another coat if water is absorbed. Keep area dry for 12 h, final effect is best after 24h. Lasts for 15 years (yeah right!).
We glued the tile, then ~1 week passed until we were able to do grouting so this should have given time for water from thinset to evaporate. Then we sealed 3 or 4 days after grout application once; then twice (probably about 30 min-2 h apart) after 12h period. So I guess close to instructions, but not entirely the same.
Additional question, --if there are places to repair (holes, cracks in grout...a few), is it ok to repair and then follow the suggested procedure for sealing these places again? How long after we are done, we should reapply sealer--5 years...or should we watch for deterioration of water repelling properties of joints?
Many thanks. I already love this place:).
04-02-2010, 09:20 PM
I would apply sealer again with a good application method so that you are leaving a good bit of sealer in the grout line to be absorbed. If you are using a sponge to apply, you will not get good coverage. If the grout is on a horizontal surface, apply it like a river in the grout lines and let it absorb for 5 minutes then wipe away the excess. Two coats of this is almost always sufficient.
You can repair the grout where needed and go ahead and seal same day. Just be sure you are not applying any thin layers of grout as they will not adhere. If you need to make a repair, dig out some of the existing grout so you have at least 2/3 the depth of the tile to install the new grout.
After whatever period of time the sealer lasts, the grout will start to absorb water again. When you notice that happening, reseal.
04-03-2010, 06:02 PM
Hi Krista, Welcome :)
Steve has guided you well. A couple of my personal opinions (you know we all have them). :D
1. I suggest the grout repair waits 72 hrs. prior to sealing. Read the grout bag directions. Some are going back to misting the grout with water for those three days. This helps the grout to hydrate and strengthen. BTW, yes it takes 28 days for any cement based product to fully cure.
2. It's not uncommon for the grout not to bead water (after initial beading when first applied) after a period of time. We call this wet out. If the grout doesn't dry within 5-10 minutes the grout does need to be resealed.
3. Use a tile & stone specific neutral pH cleaner to maintain your tile and grout. This will assure maximum longevity of the sealer. If anything acidic spills on the floor, try to clean ASAP. Anything acidic will break down your sealer.
4. The grout that you're able to scrape off with your nail may actually be over watered grout. Check various places if you can scratch out the grout with your fingernail. If you can, it should be removed and replaced.
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