The cavity boarding blocks are designed for reinforced and non-reinforced bearing walls. The blocks can also be used for non-bearing peripheral walls in underground construction parts. It is used also for building the base below the fence structure. The block profile is adapted for inserting horizontal armoring, the shape of the sideboards forms the locks which are used for simple assembly. The system of boarding blocks is fitted with the pieces for halving. Internal cavity of the block is filled with concrete mixture. It is offered in neutral grey colour with smooth surface.