There are a few probable causes but before you tear up the tile and start over try this quick cracked grout fix.
Replacing bathroom floor tile grout.
One way to change grout color is to colorize existing grout.
Leah demonstrates how to remove damaged grout with a grout saw and then re grout the damaged areas.
The old grout might be moldy and beyond cleanable.
Use a grout saw to remove the loose or damaged grout in between the tiles.
Gently run the grout saw back and forth along the grout seams.
When remodeling a bathroom or kitchen the hardest part can be removing the grout from pre existing tile.
Work slowly image 3.
Simplify the tough grout removal part with an inexpensive power grinder.
Is the grout between your floor tiles cracking or worse crumbling away.
Attach the removal unit and set the bit depth to 1 4 in.
If the width is 1 8 of an inch or smaller use an unsanded grout.
The existing grout color is no longer pleasing to you and you wish to change it.
Links to grout tools.
Be careful to avoid damaging the tiles.
Use a spray bottle and some cold water to wet the areas where you removed the grout.
Learn how to regrout bathroom tile.
The blade is harder than the grout and will cut it away image 1.
Make sure the bit is the right size for the space between the tiles and adjust the bit to the proper depth.
Grout is made from water cement and sand which hardens over time to form a rock like material.
Run the tool guides between the tiles and.
Measure the space between the tiles.
Step 3 clean the seams.
Remove all the loose and cracked grout with a grout saw or dremel tool and completely vacuum out the gaps.
It speeds up the job so you can move on the easier parts regrouting and polishing the tile.
Choose the correct type of grout based on the width of your tile joints and where the repair is being done.
If the space is larger than 1 8 of an inch use a sanded grout.
For small areas use a grout removal tool with a carbide blade.
When that day comes remove the grout and replace it to rejuvenate the installation and make the surface gleam.
Remove and replace grout even the best tiling jobs show their age eventually.
Step 2 remove loose and damaged grout.
For much larger areas use a rotary tool image 2.
How to remove grout.