Benjamin Hall Design Creates Concrete Block ADU in Phoenix for Multi-Generational Living

Benjamin Hall Design, a local architecture studio, has completed an accessory dwelling unit (ADU) in Phoenix, Arizona, attached to an existing 1970s suburban home. The project, named Moon Valley Residence, was finished in 2025 and spans 1,756 square feet. Constructed from grey concrete masonry units (CMU) for both exterior and interior finishes, the ADU was designed to house a retired couple while maintaining privacy and connection to their family in the main house. The structure consists of four rectilinear volumes at different elevations, with strategically placed openings offering views of Lookout Mountain and the surrounding golf community. Studio founder Benjamin Hall cited childhood travels through the Southwest and visits to Montezuma Castle, an ancient Native American ruin, as key inspirations for the design, influencing its scale, stacked forms, and approach to managing desert heat and light. The ADU features a curved wall for privacy from the cul-de-sac, shares an access door with the main house, and includes a wedge-shaped dining space, living room, kitchen, guest suite, and primary suite with private patios. Utilities are integrated into built-in millwork due to the continuous CMU material. The project team included Rare Form Builders as contractor and Structurology for structural engineering. Photography was handled by Logan Havens. This addition is part of a trend of residential projects in the Phoenix area, such as those by Kendle Design Collaborative and Wendell Burnette Architects.