Is it a ceramic tile or a quarry tile?

I'm not sure what the difference is, but it is rough in feel, not smooth. Hope this helps.

First thing you need to do is wash it to remove dirt and mildew and this can be done with a soultion of three parts water, one part bleach and a couple of oz of a liquid detergent (non-ammmoniated). Allow this to remain on the surface 15 to 20 minutes and rinse well.

Then prime the surface with an exterior acrylic/latex primer and topcoat with a satin or semi-gloss exterior acrylic/latex house paint. This will be for tile that is on the side of the house or roof and not for floors.