Crystal Healing

Instead of cutting about 1/4 to 1/2 inch of the 12x12 marble tiles in order to place 5 across the width of the fireplace, he took out 1/2 inch from each side of my fireplace. Near the top, there is a 1 inch gap. He said he would put wire and fill it with mortar. Would this do the job?

Also, building code says I need one foot from the right and left of the firebox. Since he sliced of 1/2 inch from each side, this would make it 11 1/2 inches. However when the tiling is done, the mortar will add the extra 1/2 inch to make it 12 inches. Would this be up to fire code?

Hope you understand the question.