Hollow tile/masonry house.

[oink]

Are you referring to a CBS (hollow concrete block) structure? If so, they are generally filled with concrete only where the steel is placed, like corners and doors and other points as needed. Sometimes the remaining voids are filled with an insulating material. A foam board is normally placed inside the concrete with the drywall on top of that. Properly constructed they are very strong. Concrete can retain some moisture. I would not use an impermeable wallpaper over the drywall.

Pua`a
S. FL
Big Islander to be.

[Rob Tucker]

Mold is a living organism and requires food, water and air to survive. Cement provides no food and is highly alkaline a PH factor that generally inhibits mold. Something else must be feeding the mold in the described situation. Often the paper on drywall is the food source (cellulose - wood fiber).

That said it must be recognized that in this climate mold can grow on glass if dirt accumulates. I think the hollow voids in the wall you describe were not clean or filled with some inappropriate material. Also it is possible some organic contaminant was used in the mortar or grout.

My 2 cents.