Case Studies

Star Lofts

Mass Timber/Light-frame Hybrid Optimizes Affordable Housing Design

Cutler Development met carbon, cost, and community goals when they demolished an old gas station and built a carbon-friendly hybrid mass timber building, creating much needed workforce housing for Iowa’s capital city of Des Moines.

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Star Lofts / ID8 Architects / KPFF / Brent Isenberger Photography

Star Lofts, named after the Star gas station that sat on the site for years, reflects the big aspirations of this small developer in their quest to build residential and commercial projects that improve neighborhoods, society, and the environment.

Using what they learned on Junction Lofts, a mass timber project in nearby West Des Moines, Molly and Scott Cutler, Partners at Cutler Development, kept the project both sustainable and financially viable by combining mass timber with light-frame wood construction. The hybrid design, slated to achieve Zero Carbon Certification™ with the International Living Future Institute (ILFI), highlights the carbon advantages of building with wood as well as the benefits of blending different construction methodologies and using materials where they make the most sense.

Hybrid Design and Creative Value Engineering Provide Cost Savings

The three-story project features commercial space on the ground floor with 20 residential units above: three studios, 14 one-bedroom units, and three two-bedroom units. The building was framed using a hybrid system of 3-ply cross-laminated timber (CLT) decking, glue-laminated timber (glulam) columns and beams, dimension lumber walls, and CLT stairs and elevator cores.

The team made additional value engineering decisions to keep the project as affordable as possible. They made the lumber-framed partition and interior walls of the residential units load bearing, which helped eliminate the need for columns on the upper stories, and chose traditional insulation for the stud cavities. They specified industrial appearance for the mass timber elements and used the CLT panel cutoffs for the stair treads. They were also surprised to find that the CLT elevator shaft saved money compared with a CMU option.

It’s not unusual for initial designs to come back as too expensive, and that’s what happened with Star Lofts.

“It took a couple iterations to land on a design that was cost effective. Our shift to a hybrid design was pivotal in terms of making this budget work. Mass timber brought efficiencies in terms of schedule and sequencing; we also benefitted in that we didn’t have to cover it with drywall. The light-frame lumber added value in other ways and was easy for crews to frame and insulate.”

– Scott Cutler, Cutler Development