Grout repair problem Advice and information on tiling and fixing tiles to a variety of surfaces

[Mark Steward]

I have a few gaps in the grouting of my bathroom floor tiles. I've tried patching using some more grout, but after a short while it comes off. The new grout doesn't want to stick to the old grout. Is there anything I can do?
Thanks Mark

[chris_on_tour2002]

i'd say that the only option is to remove all existing grout and re-apply in its entirety.

i think that this will be the only way to guarantee the result.