There are a few probable causes but before you tear up the tile and start over try this quick cracked grout fix.
How to repair floor grout cracks.
Repairing hairline cracks in grout.
Check out how easy it is to repair cracked or worn grout in your shower tub or any other tiled area.
My house is only 2 years old and i already have some.
Therefore learning how to repair cracked grout can be an essential skill to learn.
Repairing the hairline cracks in the grout lines is a fairly easy diy project.
Remove all the loose and cracked grout with a grout saw or dremel tool and completely vacuum out the gaps.
While grout may crack from wear and tear an uneven or weak subfloor.
Grout is available as sanded or unsanded.
While grout is a durable material tile surfaces suffer a lot of wear and tear that can crack it resulting in a shabby look.
If the width is 1 8 of an inch or smaller use an unsanded grout.
If the space is larger than 1 8 of an inch use a sanded grout.
Once the grout cracks for any reason it s time to repair broken grout before there is any damage to the surrounding tiles.
When ever you install ceramic tile you really should keep some of the grout stored in a cool dry place for future repairs.
It is best to do this at an angle then smooth over the grout with a wet finger.
Is the grout between your floor tiles cracking or worse crumbling away.
Choose the correct type of grout based on the width of your tile joints and where the repair is being done.
Links to grout tools.
Measure the space between the tiles.
Leah demonstrates how to remove damaged grout with a grout saw and then re grout the damaged areas.