Hello Ilia!

My wall is covered with a awning and has no earth on the ground. The floor is tiled, so no moisture is there. Except for when I clean the floor with the hose. No water will come down onto the fresco. It is a solid wall.
Do I still have to use the tar paper, I am not familiar with it and where can I find if I need it? In Miami, we have only Home Depot to find these things.
I plan to do a mosaic of broken tiles from the ground up to cover myself when the floor gets wet. Then after the fresco will come up.
How does the tar paper stay on the wall? Does the cement I apply over the tar/wire hold it up?

Thank You Very Much.
Victoria in Miami