Innovations in Housing Construction Offer Promise in Increasing Affordability
By Pamela Martineau
6 min read
How Design Features Are Helping to Reduce Costs
Housing researchers and builders throughout the nation are eyeing cutting-edge innovations in construction and design—from 3D printing, robots and drones to modular off-site construction—as methods to drive down building costs and increase affordable housing stock.
“The (lack of) housing availability and high costs are driving the need for innovation…,” said Andrew McCoy, associate director and professor at the Myers-Lawson School of Construction at Virginia Polytechnic University. “We’re seeing much more of our housing that can be produced in a factory setting.”
McCoy delivered his comments during a panel discussion in March sponsored by the Bipartisan Policy Center’s J. Ronald Terwilliger Center for Housing Policy. The Center released a report in April of this year titled “How Can Construction Innovation Make Housing More Affordable?” The report, authored by Arica Young, outlined some of the new technologies being deployed and explored in the affordable housing space.
“New materials and innovative building processes can help streamline and shorten the production process, improve overall cost and efficiency, and even reduce greenhouse gas emissions from the building sector,” the report states.
Mass Timber and Tall Wood
Mass timber manufactured building materials are currently being deployed to reduce construction costs. Mass timber is a product manufactured in a factory from pieces of wood that are connected with nails, glue and other materials. Glue-laminated timber (glulam) and cross-laminated timber (CLT) are two common forms of mass timber. Glulam consists of wooden boards pressed together on the parallel, while CLT is connected in a perpendicular pattern.
These mass wood products are used in what builders and researchers call “tall-wood” buildings, which are multistory buildings that use the products.
Judith Sheine, professor of architecture at the University of Oregon and director of design at the TallWood Design Institute, described the use of mass timber and tall wood on a pilot project of 34 affordable housing units in Milwaukie, OR. Sheine, also speaking at the panel discussion, said mass timber has an added benefit of aiding wildfire reduction since it often uses trees under ten inches in diameter. This so-called brush is often cleared from forests to reduce wildfire risk.
“It has co-benefits of wildfire reduction,” Sheine said. Mass timber was used in a seven-story mixed-use affordable housing development in Boise, ID. Sheine said mass timber also has been used in energy retrofits in affordable housing communities.
Structured Insulated Panels – SIPs
The report also cites structured insulated panels—or SIPs—as another innovative building material that can cut costs and increase insulation, allowing for higher energy efficiency in buildings. SIPs consist of two sides of strand board with an insulated foam core at the center. They are wind resistant and have load-bearing capacity. The panels are fabricated in such a way to allow them to fit together on a construction site, which reduces the cost of expensive framing work from skilled carpenters. An affordable housing development in Grand Junction, CO used the product and according to the BPC report, the construction time was cut by at least two months.
The upfront cost of SIPs can be more expensive than traditional wood to purchase but creates cost savings through lower construction time and labor expense. On larger buildings, due to economies of scale, the cost of SIPs is reduced.
Prefabrication and Modular Buildings
Builders are increasingly turning to prefabricated or modular buildings to speed up build times and, in many cases, lower construction and overall costs. Prefabricated modular homes are built in large part in factories. Under this process, sections of a housing unit are built in a factory and transported to a housing site for assembly. With volumetric modular construction, fully enclosed six-sided buildings are completed in factories and then transported to a housing site and installed there. Often, prefabricated homes use materials, such as SIPs or mass timber.
Prefabricated housing decreases time spent on a build site, which can lower neighbor complaints during construction and also lower the amount of time workers need to travel to a work site, thereby cutting CO2 emissions.
Small prefabricated “tiny homes” are increasingly used to house the unhoused. The homes are sometimes arranged in villages near social service providers. The speed at which the homes can be assembled is part of their appeal when used for this purpose.
Some states—including Idaho, Minnesota, Montana, Nebraska, South Carolina and New Jersey—allow third parties to inspect prefabricated homes within the factory setting. This eliminates the need for local inspectors to come to a work site to perform all inspections.
According to McCoy, the market is much more accepting of prefabricated housing. There’s been considerable progress made in recent years in manufacturing processes, cost efficiencies and the development of national building codes.
Prefabrication is not just being deployed in residential housing. It is being used in commercial buildings as well. Prefabricated elevator cores have been developed that are built off-site, then lifted by a crane into a building. Sections of ducting also are built off-site.
3D Printing, Robotics and Drones
Numerous new technologies are being used to cut human labor in housing construction, speed build times and aid precision in tracking work sites and materials. The technologies include 3D printing, robotics and drones.
3D printing in home construction—also called additive manufacturing—is a process where robotic extruders and other machines form components of a building by pouring layers of concrete or other materials into mold-like structures. The process can build frames and walls, but not currently a home’s windows or plumbing.
The process is not yet widely used but is being eyed as a way to help alleviate the housing crisis by providing another way to build homes quickly at lower cost. Habitat for Humanity built a 3D printed home in Virginia, which was estimated to have cost 30 percent less than a traditional stick-built home.
McCoy highlighted how robots are being studied and, in some places, deployed for use in construction to perform such tasks as bricklaying, painting and demolition. Some sites are now operating construction equipment via computer and drones are being used to survey build sites to track materials and other elements. Computerized, image-based inspections via photogrammetry also are being performed on buildings and construction sites.
“We’re seeing robots starting to lay brick, lay concrete,” McCoy said. “This helps to reduce worker injury. Robots can go into much more unsafe settings.”
McCoy said innovation in construction requires investment—both public and private—but “the knowledge created by one firm creates value for other firms.”
In the end, innovation may help to reduce costs and increase the nation’s housing stock – a goal sought by builders, policymakers and consumers alike.
“Builders are actively looking for ways to reduce costs right now,” McCoy said.
