This disclosure is a system which includes processes, machines, articles of manufacture and compositions of matter required to construct a habitable structure comprised of a cementitious product, preferably autoclaved aerated concrete ("AAC"), formed in unique blocks, panels and beams. This results in an extremely environmentally friendly habitable dwelling, residential or commercial, which, due to the resultant synergy of embodiments, when compared to a similar structure employing prior art and/or current industry's standard materials and methods of construction, is structurally superior and simultaneously yields substantial savings in labor, time and costs.