A modular building system is provided which includes modular wall sections. Each wall section has a concrete support column reinforced within by metal rods and at least two wall panels which are formed of concrete. Spline panels are attached to the wall panels at one or both ends of each wall section to connect the wall section to an adjacent wall section. The spline panels are formed of concrete and have a width less than half a width of any of the wall panels. The spline panels are positioned so that a portion thereof extends further in a longitudinal direction of the wall section than the respective wall panels to which the spline panels are joined, so that the spline panels cover joints between wall panels of adjacent wall sections when the adjacent wall sections are connected.

The invention relates to a method for producing a building as a timber-frame construction, frame construction, or post-and-beam construction, having a supporting framework consisting of pillars and/or struts, comprising the following steps: a) in the regions of subsequent pillars and/or struts of the timber-frame construction, frame construction, or post-and-beam construction plate-shaped wall building elements are provided with screws in such a way that the tips thereof protrude into the subsequent pillars and/or struts; b) behind the plate-shaped wall building elements shutterings for the supporting framework consisting of pillars and/or struts are produced from strips and/or insulating material; c) the shuttered regions for the framework are filled with a load-bearing, curable compound, in particular with concrete, wherein the hardening compound flows around the screws used in step a); d) after step a), at the latest after the curing of the compound, the plate-shaped wall elements are set up, fixed, and aligned; e) installation elements for electrical power, water, heating, etc. are mounted on the outer face of the plate-shaped wall building elements; f) plate-shaped wall building elements are fixed to the outer faces of the pillars and/or struts of the supporting timber-frame construction, frame construction, or post-and-beam structure; g) the remaining spaces between the plate-shaped wall building elements, the elements of the supporting framework, and/or the installation elements for electrical power, water, heating, etc. are filled with a bulk material or an insulating material.