Triangular stud shaft wall system

A shaft-wall assembly comprising:

• a shaft wall having upper, lower, left and right sides;
• a first runner positioned adjacent to the lower side of the shaft wall, a second runner, positioned adjacent to the upper side of the shaft wall, wherein each of the first runner and the second runner comprises:
• a substantially planar transverse middle section having opposed first and second longitudinal sides each having a length and opposed first and second ends each having a width, wherein the length of each longitudinal side is greater than the width of each end;
• a first upstanding section and a second upstanding section, wherein the first upstanding section has a first height and the second upstanding section has a second height, the first upstanding section extending to the first height from the first longitudinal side of the middle section, and the second upstanding section extending to the second height from the second longitudinal side of the middle section, wherein the first upstanding section and the second upstanding section are substantially parallel;
• a triangular stud of the shaft wall between the first runner and the second runner, the triangular stud having a triangular polyhedron shape comprising three sidewalls defining a triangular bottom perimeter and a triangular top perimeter;
• the first runner and the triangular stud sized for a first said side of the triangular stud to contact the first upstanding section of the first runner and a vertex of the triangular stud opposed to the first side of the triangular stud to contact the second upstanding section of the first runner.