March 23, 2020
The construction industry is developing new methods and improving productivity in response to customer needs, technological advances and labor-related challenges. Prefabrication is at the forefront of this evolution, delivering high-quality projects with lower costs and accelerated schedules.
For some, the term ‘prefabricated’ may spark memories of manufactured housing from the last century. But the prefabricated components used in construction today blend seamlessly into completed buildings and contribute to an efficient workflow.
“Concepts like DfMA—design for manufacture and assembly—and DIMC—designing for industrialized methods of construction—are on the rise,” said DPR’s Ray Boff.
According to Buildoffsite, DfMA, in its simplest terms, is “the application of factory (or factory like) conditions to construction projects” and almost always includes prefabricated components. Parts of the structure are manufactured offsite in a controlled environment. These pieces are then delivered to the jobsite and hoisted into place for assembly.
“DIMC evaluates how available building components can be programmatically arranged and procured in the most efficient ways to provide cost and schedule certainty, along with improved design and construction quality,” said Boff. “Both concepts support concurrent engineering methodology.
But what about creativity? Does building with prefabricated components restrict customization in design? Not at DPR.
“Each project is a blank canvas,” said DPR’s Bryan McCaffrey. “Through the use of virtual design and construction, and the data-rich model produced through the VDC process, we have the ability to digitally fabricate custom components.”
DPR works with Digital Building Components (DBC), located in Phoenix, AZ, to digitally fabricate precise-to-spec building assemblies directly from the building information model (BIM), including load-bearing panelized structures, fully finished panelized exterior walls and panelized interior walls with electrical and plumbing already roughed in.
The key to integrating prefabrication is to include it from the beginning of the design process. DPR collaborates with customers, architects and engineers to determine if prefabrication makes sense and how best to include it. This helps ensure that the project will run smoothly. It also avoids the challenges arising from inserting prefab into an existing design.
Incorporating prefab into a project’s design can yield the following advantages:
- Higher Quality: Digitally fabricating components in a factory-controlled environment improves quality control. Machines create precision products directly from the model and deliver components that fit as expected in the field.
- Cost Certainty: Materials are batched, and waste is reduced or eliminated. Factory-based labor offers greater predictability that results in higher productivity, safer working environments and cost advantages. According to Buildoffsite, site labor costs about 2.2 times as much as factory labor and factory productivity is about double that on jobsites.
- Accelerated Schedules: Panels are manufactured in parallel with work done in the field. This leads to earlier project completion. Weather doesn’t affect factory production and thus becomes less of a factor.
- Improved Labor Resources: A recent survey by AGC found that “80% of contractors report difficulty finding qualified craft workers.” Prefab requires fewer workers, provides a safer work environment, and offers consistency - making jobs in the prefab sector among the most attractive in the construction labor force. Controlled environments also allow for cross-training in specific tasks, which helps in labor balancing, skills enhancement and workforce improvement across the board.
- Sustainability: According to the World Economic Forum (WEF), “About 40% of solid waste in the United States derives from construction and demolition.” Prefab batches production and takes place in a controlled environment, substantially reducing or eliminating waste. It also reduces the number of vehicles traveling to and from the jobsite, thereby reducing the consumption of fossil fuels and their associated emissions.
- Other job-specific advantages may exist: Jobsite constraints are becoming more common. Prefabrication minimizes the number of workers required on-site. According to Sam Huckaby of Vantage, having fewer people on the jobsite was a significant benefit of using prefab. “We were a constrained site from a parking and access perspective, so the more work we were able to do offsite, the better, especially when something is wrapping the entire building…”
Prefab in Action
The 175,000-sq.-ft. Building 1 on the Vantage McLaren Santa Clara data center site was DPR’s first use of pre-finished EIFS panels from Digital Building Components. The digitally fabricated exterior panels allowed the team to enclose the building nearly 12 weeks earlier than if it had been stick-built.
In a series of higher education projects in California, DPR also provided prefabricated steel panels in place of wood framing, without increasing the owner’s cost. According to the owner, the projects realized the following benefits by including prefab:
- Efficiency of construction
- Improved schedule
- A stronger, better product for the same cost.
Ultimately, the power of prefab is in the value to the customer and project. Digital prefabrication employs advanced technology to improve quality, lower costs and speed up the schedule, while leveling out the labor. Improved modeling capabilities that streamline the connection between design and construction place prefabrication at the forefront of the technology revolution that is transforming construction.