Breathable boundary wall system

A breathable boundary wall system for closely spaced "Zero lot" building constructions comprising: at least one load-bearing substrate for supporting a first wall section; the first wall section comprising: a frame section 130, the frame section comprising at least first and second opposing major faces 131 and 132. A breathable cladding material 140 is fixed to the first major face of the first frame section, for forming an external cladding on the first wall section; and a second wall section erected on a load bearing substrate and spaced apart from the first wall section to define a gap 180 therebetween; wherein the first wall section and the gap defined between the first wall section and the second wall section together define the breathable boundary wall system. In preferred forms the wall system includes a capping across the gap. 170142 10 142 120 -... 148 14 Fig...2