Hi - I am having a dispute with my husband about installing a stucco wall. He has been told you must fill the cells (grout the walls) with concrete - prior to applying the stucco finish of course. I disagree. While growing up in California I watched contractors install many a block wall and they never filled the cells with concrete, they only applied the concrete between blocks when building the wall. So, will our wall fall down or stucco crack if cells are not filled with concrete? Main reason to ask of course is the money involved in filling the cells - if not needed, why do??? thanks