I have a question about air in mortar.
I am remodeling my bathroom. First, I demolished my 25 year old tub and shower surrounding tiled walls. They were built with regular drywall and white ceramic 4 and 1/4 by 4 and 1/4 inches tiles. Me and my wife used tub and shower every day, but all walls were still in a very good condition.
I used a cold chisel to remove all tiles one by one before I removed the walls.
I found that adhesive used to attach tiles to wall was combed (notched), but did not cover entire tile surface for most of tiles. That means that there was some air between tiles and walls. But still after 25 years it took for me some time and effort to remove all tiles.
Now goes my stupid question:
Why is it so bad to have occasional air bubbles between tiles and walls?
Again, this question may look like very stupid, but I still would like to hear some opinion.
The less adhesive on the tile, the more likely the tile will loosen and allow water behind the tile face. Ideally you want 100% coverage. Years ago, before concrete board and solid substrates, mud jobs were the rule. Concrete blobs the size of english muffins were used to set 4x4" tiles on a scratch coat over metal lath. These blobs covered about 75% of the tile and hold tenaciously to this day. I see bathrooms done in the '20's and '30's that are rock solid.
Your tile held up, that is not always the case.
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."
B. Franklin 1759