QUESTION

We have an apartment clubhouse with exterior glazed ceramic tile on the porch. During rainy, foggy, high moisture days water pools on top of the tile. Makes it dangerously slippery. Could this pooling be caused from a lack of a vapor barrier under the slab that I read about on your page or something else? I don't know that the barrier was left out. Thx

ANSWER

ANSWER - A vapor retarder goes under the concrete slab and doesn't have anything to do with water pooling/collecting on the tile surface.

Industry standards require that the exterior tile surface that is subjected to wet conditions have a slope towards a drain of 1/4" per foot.  It sounds like in your case the installer did not adequately slope the tile installation so water would readily drain away.