Home Building Enters the 21st Century
Building a home hasn't changed much in the past century. The general contractor orders tons of raw materials. Trucks back up and everything gets dumped at the job site. Soon, subcontractors and framing crews go to work nailing, gluing, and screwing the house together.
It's a process that takes, months or even years, depending on the size of the house. It's also a process that's wasteful--as much as one third of the raw materials purchased to build a conventionally framed house end up in a landfill. Then there's the issue of quality, which can vary greatly through the course of construction, depending on who shows up to the job site on any given day.
"You wouldn't let a car company dump a bunch of materials in your driveway and have people you don't know show up to build you a car in the dust, or rain, or cold," said Tedd Benson, founder and company steward of Bensonwood Homes. "But that's the way homes are built everyday."
Fortunately, something is being done to bring homebuilding into the 21st century. Bensonwood is collaborating with the Massachusetts Institute of Technology House_n Research Consortium, along with several companies in the building industry, in a program called the OPEN Prototype Initiative.
Their goal is to build four prototype homes, deploying advanced designs, materials, systems, and fabrication strategies. The first prototype, called OPEN_1, a three-story 28 ft. by 46 ft. house, was completed in only thirty working days. The house is located in Greenfield, New Hampshire, at Crotched Mountain, a school, hospital, and rehabilitation center. OPEN_1 houses people with brain injuries who are in the process of transitioning back into the general community.
Untangling the Web
Key to the OPEN Prototype Initiative is "disentanglement," wherein the jumble of items that make up a house--namely the frame, walls, wiring, and plumbing--are separated from each other into separate systems. Disentanglement offers a host of benefits. First, all of the elements are easily accessible for repair, replacement, and reconfiguration. Second, because the house is now configured in separate elements, it can be built in subassemblies. A house that is built on site from 50,000 pieces, often in trying conditions, can be built into about 50 extremely precise subassemblies in a clean, warm shop by career-minded craftspeople.
"We're already doing a lot of disentanglement," Benson said of the OpenBuilt® homes they currently offer. Indeed, the walls and roof of a Bensonwood home are attached to the timber frame, while wiring, ducting, and plumbing run neatly through chases and a large second floor space that is easily accessible. A Bensonwood timberframe is built in the shop and then quickly assembled on site. The same is true of the insulated panels. They have windows, wallboard and even wainscoting installed at the shop, before they're shipped to the job site, where they're quickly raised into position by crane.
Going Forward
OPEN_1 takes the current Bensonwood process forward by an order of magnitude. "We built the OPEN_1 Prototype into forty subassemblies at our shop," Benson explained. Wiring was preinstalled with prototype plugs to allow the wiring in each subassembly to connect to the entire house. The plumbing was run in a central "core" subassembly.
Interior portions of the walls were already finished and painted and exterior siding was also installed and painted on each subassembly. Because the subassemblies were built with extreme precision using computer-aided design and manufacturing, it was simply a matter of flying them into position and attaching them together at the site. When the OPEN_1 was completed, the total construction waste on the site fit into two thirty-gallon trashcans.
More Innovation
The schedule calls for a new OPEN Prototype Initiative house to go up every 18 months. OPEN_2 is likely to be a single-family home with flexible interior spaces, made possible by moveable walls that snap into place. "You'll be able to move everything around like Legos," Benson explained.
With baby boomers aging and more likely to stay in one place, the ability to easily reconfigure a home when children move out or someone can no longer climb stairs, will no doubt be a welcome offering.