Tile Mailbox

Two years ago I made a mailbox by affixing ceramic tiles to a metal mailbox. The grouting was above my skill level so paid someone who did a great job.

Now a small piece has fallen off and I plan to put that back on. However, mailbox can not be taken off the post.

What I want to do is "seal" the tile/grout so water can not get in. There are some tile water sealers at Home Depot but not sure if I need that. Tiles are ceramic so my guess is they should be ok, but not sure about that.

I am leaning toward some type of grout sealer but want something easy that I could just apply to the grout. Should I just go to Home Depot and buy it there? What would be best, spray? liquid?

Thank you.

-Steven

What I want to do is "seal" the tile/grout so water can not get in.

Can't be done.