Housing, Industrialized: Designing for Off-Site

With one slight change to his floor plan schematic, architect Ryan White increased the production of a new single-family project by 33%.

How? By shaving just a foot off the depth of the three-story, side-by-side duplex destined for an infill lot in Pittsburgh, he enabled Structural Modular Innovations to build three boxes at a time on its factory floor instead of only two.

“Understanding the capabilities of the factory allowed us to meet the attainability goals for the project,” says White, director of design at Dahlin Group, in Irvine, Calif. “And losing that 1 foot didn’t affect the livability or marketability of the homes at all.”

As more home builders look to alternative production solutions such as modular and full-scale panelization to combat a chronic skilled labor shortage, volatile structural materials prices, and an increase in the overall cost to build, the level of design detail and collaboration with providers for new homes is paramount in achieving the benefits of industrialized construction.

“Design casts the biggest shadow in the whole process,” says Sara Logan, AIA, VP of design and Volumetric Building Companies, a vertically integrated modular provider based in Philadelphia. “When you look at a building as a product instead of a project, you realize that what you spend on design [typically 2% to 5% of the overall budget] has significant implications on bigger costs, such as materials [50%] and labor [15%].”

Design for Construction — in a Factory

“Before we submit anything to the building department, we know how the house is going to be built,” says Donald Carpenter, VP of product development at Oakwood Homes, in Denver, which incorporated panelization 20 years ago. “It’s about embracing manufacturing principles that everything has to be decided and designed beforehand.”

In large part, that’s a testament to the ever-advancing technical wizardry of various computer design and modeling software programs that not only build a house and all of its elements virtually, but provide the factory and the field with precise documents and detailed spec lists that take the guesswork (and rework) out of the equation.

“We’re able to walk these houses virtually, and not just a framed house, but with all of the MEP [mechanical, electrical, and plumbing] in place,” Carpenter says. “One of our absolutes is we don’t make field decisions, so everything has to be thought out. And if it does happen, it’s brought back to the product development team [to refine the drawings].”

Rich Binsacca, editorial director of Pro Builder Media, provides more details and benefits of the off-site design process in this Pro Builder article, which originally appeared in the May/June 2023 issue.

NAHB will also host the Building Systems Housing Summit — a one-of-a-kind conference dedicated to offsite construction — at the National Housing Center on Oct. 15-17 for those interesting in learning more about off-site construction and networking with prominent industry professionals. Register now to attend.