Stack pattern (SP) masonry construction is experiencing rising demand from homeowners, designers, and stakeholders, primarily due to its pleasing aesthetics. However, these stakeholders often lack awareness of the specific design constraints imposed on stack pattern reinforced concrete masonry walls by Canadian masonry design standards. In contrast, the American masonry code allows stack pattern masonry construction under certain conditions. This distinction in design standards significantly impacts the behaviour of stack pattern walls and is primarily informed by a single experimental study. To address the need for more comprehensive research on the performance of stack pattern construction and its counterpart, running bond (RB) construction, this experimental study was designed. Two reinforced concrete masonry walls each measures 4.0 m high × 2.4 m long × 0.2 m thick. These walls included 2–20 M vertical reinforcements spaced at 1200 mm and were constructed using both stack pattern and running bond methods. Subsequently, the walls were subjected to out-of-plane and constant axial loading. Additionally, ten concrete masonry prisms—five for each construction pattern were tested under monotonic compression loading. The results show that the flexural performance of stack pattern walls is 11% lower than that of their running bond counterparts. It can be found that both SP and RB walls exhibited similar failure modes but different out-of-plane displacement profiles. The results of this experimental study have the potential to influence the development of more adaptable Canadian masonry design standards and more stringent American masonry design codes, thus promoting harmonization between the two nations.