With the block formwork in wood-cement thickness of 30 cm, insert insulating polystyrene with graphite 7 cm thickness, load-bearing external walls are made. The blocks, which have horizontal and vertical tongue-and-groove joints, are laid dry, without mortar. Every 1.5 metres (six courses of blocks) are inserted reinforced bars horizontally and vertically and filled with concrete. With one simple and fast operation we obtain a bearing wall fit for use in seismic areas and with high thermo-acoustic insulation properties, remarkable thermal inertia, good breathability and REI 180 fire resistance. Mineralised cement-wood, is a natural product, certified as complying with green building standards and obtained from new pinewood recycled in a low-emission production process.