We have installed a reccessed (below grade) patio. We used castible concrete cobblestone pavers. We were planning on building a 2 1/2 ft. stone retaining wall around the perimeter. We were palnning on using the compressed gravel and casted cobblestone for a footing. But now we are reconsidering this decision based on information suggesting a 12" deep footing. We would have to pull up the cobblestones and we are wondering if a footing is absolutely necessary.
Also, we are confused about the mortar mix. A local masonry supply house recommended the following formula: 1 part cement, 4 parts sand, 1/2 part lime. However, books on the subject recommend the following mix: 1 part cement, 4 pats sand, 1/2 part fire clay. They specifically state that you should not use lime.