what is wrong with them? cracked/broken,need replaced,scratched,discolored,need regrouted,need caulking??
Are they loose?
What is wrong/how are they broken? Photos help.
need caulking, what is the correct product to apply
Tile grout is cheap. Get it at any hardware.
Remove any loose grout.
Sweep or vac is better.
Wash it clean
Mix grout in a cheap bucket. Apply with a trowel used for tuck pointing a fire place or other bricks.
wet a cloth. And wipe it all excess grout . Let it rest a day
seal your-job with grout sealer at any hardware.
Let it sit about 5 hours. Throw away the bucket. Your done
Tired it and thanks for the clear and helpful hint