A method of building a dry wall building comprising - providing building blocks (3, 4) and joining blocks, wherein opposite top and bottom sides (17; 19) of the building blocks each comprise at least one groove containing a support surface, wherein opposite top and bottom sides of the joining blocks each comprise at least one structure, in particular at least one rib, fitting at least one of the grooves of a building block and having a support surface; and - stacking alternating layers (B; J) of building blocks and joining blocks on to each other with the top and bottom sides (17; 19) of vertically adjacent building blocks oriented towards each other and the joining blocks being at least partly received in the grooves of overlying and underlying building blocks such that in each vertical pair of a building block and a joining block received therein the respective support surfaces (33; 40) engage each other and support the respective higher block (3; 5) on the respective lower block (3; 5); wherein in each building block a first groove is formed, in particular cut, into one of the top and bottom sides (17; 19) of the building block and a second groove is formed, in particular cut, into the opposite one (19; 17) of the top and bottom sides, and wherein at least one of a position, shape and orientation of the support surface in the building block of said second groove is formed relative to a reference (33; 65; 77, Hcb), wherein the first and second grooves are formed relative to the same reference (65; 77, Hcb), in particular being formed simultaneously relative to the same reference (65; 77, Hcb), wherein the reference (65; 77) is provided by one or more objects, e.g. a rib, a rail, a conveyor belt, one or more rollers or combinations thereof, or a working position (Hcb) of a cutter, and/or wherein the reference is provided by at least one of a position, shape and orientation in the building block of at least a portion of the first groove, in particular at least the support surface of the first groove. - providing building blocks (3, 4) and joining blocks, wherein opposite top and bottom sides (17; 19) of the building blocks each comprise at least one groove containing a support surface, wherein opposite top and bottom sides of the joining blocks each comprise at least one structure, in particular at least one rib, fitting at least one of the grooves of a building block and having a support surface; and wherein opposite top and bottom sides (17; 19) of the building blocks each comprise at least one groove containing a support surface, wherein opposite top and bottom sides of the joining blocks each comprise at least one structure, in particular at least one rib, fitting at least one of the grooves of a building block and having a support surface; and - stacking alternating layers (B; J) of building blocks and joining blocks on to each other with the top and bottom sides (17; 19) of vertically adjacent building blocks oriented towards each other and the joining blocks being at least partly received in the grooves of overlying and underlying building blocks such that in each vertical pair of a building block and a joining block received therein the respective support surfaces (33; 40) engage each other and support the respective higher block (3; 5) on the respective lower block (3; 5); wherein in each building block a first groove is formed, in particular cut, into one of the top and bottom sides (17; 19) of the building block and a second groove is formed, in particular cut, into the opposite one (19; 17) of the top and bottom sides, and wherein at least one of a position, shape and orientation of the support surface in the building block of said second groove is formed relative to a reference (33; 65; 77, Hcb), wherein the first and second grooves are formed relative to the same reference (65; 77, Hcb), in particular being formed simultaneously relative to the same reference (65; 77, Hcb), wherein the reference (65; 77) is provided by one or more objects, e.g. a rib, a rail, a conveyor belt, one or more rollers or combinations thereof, or a working position (Hcb) of a cutter, and/or wherein the reference is provided by at least one of a position, shape and orientation in the building block of at least a portion of the first groove, in particular at least the support surface of the first groove. wherein in each building block a first groove is formed, in particular cut, into one of the top and bottom sides (17; 19) of the building block and a second groove is formed, in particular cut, into the opposite one (19; 17) of the top and bottom sides, and wherein at least one of a position, shape and orientation of the support surface in the building block of said second groove is formed relative to a reference (33; 65; 77, Hcb), wherein the first and second grooves are formed relative to the same reference (65; 77, Hcb), in particular being formed simultaneously relative to the same reference (65; 77, Hcb), wherein the reference (65; 77) is provided by one or more objects, e.g. a rib, a rail, a conveyor belt, one or more rollers or combinations thereof, or a working position (Hcb) of a cutter, and/or wherein the reference is provided by at least one of a position, shape and orientation in the building block of at least a portion of the first groove, in particular at least the support surface of the first groove.