QUESTIONExterior Tile Installation - We purchased some ceramic tiles showing St. Jude in Santa Fe recently. We would like to use them outside in a small shrine. What should they be mounted on, with what type of mastic and what kind of grout. Maryland weather can be freezing or hot. The tiles would be covered on top, back and sides but open in the front.
ANSWERANSWER - I will briefly give you some idea of how you need to proceed. Our company does consult with architects and owners on specifying installation systems at the rate of $200 per hour and we could assist you if you wanted to employ our services.
Concrete is always the best surface to attach tile.
Never use mastic on exterior applications because it isn't a long lasting type of adhesive.
Climatic conditions are important. Your tile needs to be a freeze thaw stable with a water absorption rate of less than 3% or it can be damaged from the freezing. You need to use a quality type of sealant at the transition joints such as an exterior grade silicone sealant. Grout can be cementitious if the rest of the system works well. There are impervious epoxy grouts you can use. I would also recommend using a waterproof membrane over the concrete substrate before you attach the tile.
You should visit our Expert Answers and in the Resources column go to Installation Products to see some of the various products and systems available.