How can I seal a gap in some cracked grout?

I would fill them with a silicone based grout so its a lot less prone to cracking. I would also consider putting a couple of coats on a grout sealant to help stop this in the future.

Sharing a helpful article with an option for instructions to remove the old grout before repairing: https://www.familyhandyman.com/project/how-to-repair-grout-that-s-cracking/

You can also try connecting with a skilled handyman via video chat to discuss at hellodwelling.com

Hi! I remove old grout before replacing it. But, the first thing I would do is make sure there isn't a leak. Once any water issues are addressed, I would remove the old grout, put in new, and seal it. Good luck and stay safe!

Hi, yes you should first find out where the water is coming from and fix that.

There is good information here:

https://www.hunker.com/13414726/how-to-fix-common-grout-problems

You need to fix the water leak before anything. The water could be doing some damage and left unchecked this will just get worse generally.

if you have seepage of water then you need to fix that first so this doesn't continue then you could put a pan under the washer as well

then replace the grout ~https://www.youtube.com/watch?v=-ExyJO6b268

Hi Tracy, here is some instruction that should hep you out,

https://www.youtube.com/watch?v=9IUguMjAwzA

Is there water seepage or was the grout not properly applied? If there is seepage, you need to fix that. Otherwise get a grout remover tool at the hardware store, and buy some grout to fill it properly. If this is a new job done by a contractor, call them to come back to repair.

You need to by the same kind of grout that was applied. Sanded or unsanded.

Hello. I would consider getting a grout saw and redoing the grout.

How level was the underfloor before the tiles were installed?

I am wondering if when the washing machine was put back in place on top of the tiles, if its weight has caused some of the tiles to pull away from each other, therefore causing the crack

You can add grout to the existing. It probably didn’t have enough applied at installation.

Since the cracks are under a washing machine I would assume the weight and movement of the washer caused the cracks. You would need to remove the grout and apply new grout. Use a latex or epoxy based grout and seal with grout sealer. Regular grout is too stiff and cracks can come back.

You might try some rubber vibration pads to reduce washer induced cracks. I would remove grout and add new. Let's hope the tiles are not causing the problem - insufficient thin set under the tile. Tap the tile with a plastic end of a screwdriver. If it sounds hollow and not like the rest of the tile, then it indicates improper installation.

There are some great posts on fixing grout if you want to scroll through these:

https://www.hometalk.com/search/posts?filter=fix%20grout

Thanks all 😊, appreciate the suggestions...the washing machine hadn’t been installed at that point, and the installer didn’t get back to me when I asked his advice, so I filled it with polyfilla, and cabinets were installed over the sealed crack the next morning. Fingers crossed that will keep any Potential seepage Bay!

Here are some ideas: https://www.hometalk.com/search/posts?filter=fixing%20grout

That means you have a leak or your floor is settling .. I would for sure look into that