A Home Like No Other
The University of Maine’s Bio-Home Technology is Opening Doors in Affordable Housing
By Carole VanSickle Ellis
The oldest prefabricated home on record is the “Manning Portable Cottage,” which was created by British carpenter John Manning, who, in 1830, offered buyers the opportunity to commission house components that could be built in London, then shipped around the country or internationally and assembled upon receipt.
The concept spread like wildfire due to the relatively inexpensive production process and the added benefit that the properties could be assembled by individuals with less training, on the whole, than would otherwise be needed for home construction. Kit houses gained popularity over the course of the century following Manning’s invention, and, during World War II, prefabricated homes for labor crews were invaluable in providing fast, effective shelters that could be both erected quickly and transported relatively easily.
By the end of the war, public demand for this type of house was rampant and remains so today. However, like almost any other form of housing, prefabricated housing comes with some inherent issues that add costs — financial, time-based, environmental, and on resources — that can make even this dynamic housing option difficult for many residents to access. The multifaceted issue of cost of production is one that Habib Dagher, executive director of the Advanced Structures and Composites Center (ASCC) at the University of Maine, and his team hope to solve with a groundbreaking bio-based printing tool that could revolutionize the construction industry and affordable housing.
An Innovative Application for Existing Technology
Dagher and his team, which includes chief operating engineer in additive manufacturing at ASCC Evan Gilman, have spent nearly two decades working on projects in development of biobased materials suitable for additive manufacturing. Gilman explained that although additive manufacturing itself has been used in a variety of fields for years, the manner in which the ASCC scientists apply the principles in this field to everyday problems such as creating comfortable, affordable, long-term housing for the roughly 7 million Americans who do not currently have access to such habitations at this time is very new.
Traditionally, Gilman explained, additive manufacturing with polymers has been used to create relatively small-scale objects rather than something big like a fully functional residence capable of housing multiple residents on a permanent basis.
“The basic technology has existed for a long time, but we are pushing the boundaries of how large a format we can use with additive manufacturing,” Gilman said. “We are printing, layer by layer, the floors, the walls, and the roof all together in one complete shape.”
Dagher added, “We are using a technology very similar to what is used on small 3D printers, but we are melting a polymer with wood fiber in it and depositing that bio-based material using a nozzle — and at a much faster rate than a small printer.”
That speed is increasing all the time as the team continues to refine the process; by the end of the first prototype’s print run, the machinery was printing almost six times faster than the speed at which it had begun. “The other thing that makes this technology different — and the most important element — is that the materials are 100% bio-based and 100% recyclable,” Dagher said. “That means the entire house is recyclable.”
Bio-based materials are products that mainly consist of one or more substances derived from living matter, also referred to as biomass. In the case of the ASCC home, the bio-based construction materials that are used to “print” the structures are primarily bio-resins and sustainably sourced wood fibers. Maine has a particularly accessible source for this material in its forest products industry, which creates a great deal of wood fiber and other wood byproducts that fit the bio-home bill perfectly. Historically, the state’s papermill industry has purchased and used large volumes of this “waste,” but the papermill industry has struggled in recent years and all but six of Maine’s paper mills were closed by the start of 2023.
“There is an excess of wood fiber in the northeast that is currently looking for a home,” Gilman observed. If we can use those excess materials or residue to produce a home, it makes them useful again and creates a valuable structure like a house.” He added, “Housing is a good potential application for the technology because there is a big need. We have excess material available and a real need for housing.”
Dagher noted that the bio-homes also function as “carbon storage and sequestration facilities” because they are made from trees that have captured carbon from the air and that are then converted into bio-based homes that retain that locked-in carbon. “This makes the entire process and product very unique because of its recyclability and environmental friendliness,” he said.
Next Steps: Weathering the Storms, Literally
In late 2022, Dagher and his team revealed the culmination of their bio-based printing project: the world’s first bio-based, 3D-printed home. The prototype boasts 600 square feet of living space and architectural features largely created from recycled and repurposed materials. In the future, Dagher noted, other elements like kitchen cabinets, could be printed along with much of the rest of the structure. Already, the sleek model is being compared to work by famous architect Frank Lloyd Wright, who also had a passion for affordable, visually attractive housing.
Wright’s efforts in this arena were a valiant precursor to the Maine team’s bio-homes, but they, like most prefabricated options prior to the ASCC’s prototype, had one prevailing handicap that limited universal applicability to the problem of affordable housing: They were made of ready-cut pieces composed of traditional building materials that had to be transported to the building location and then assembled.
Other creative minds have attempted to solve this problem by bringing 3D printers to the construction site and printing out concrete walls that may be topped with traditional roofs once assembled, but the process is still costly and not particularly efficient. By using bio-based materials, the entire structure can be printed as one complete unit on- or off-site and installed on a concrete slab via crane.
“With concrete printing, typically you only get to make the walls out of that printed material, then you go back to more conventional materials for the rest of the house,” Gilman explained. “We print the whole structure of the house using these environmentally friendly materials that we want to use and that only require the presence of a foundation for installation.”
The prototype itself is now installed on its own foundation, and the research team, along with community action agency Penquis, a Maine-based nonprofit focused on developing affordable housing around the state, is actively monitoring how the building endures what is shaping up to be quite a harsh Maine winter. Penquis plans to purchase the first nine houses printed after the prototype, explained the agency’s housing development director, Jason Bird.
“The pilot project involves the purchase of nine homes to further the testing on the models. We will help tweak the design and install those homes in a development customized to serve households and individuals experiencing homelessness,” Bird said proudly. Penquis anticipates the bio-homes could serve as permanent homes for their residents in many cases.
In addition to withstanding difficult cold-weather conditions, the buildings will also be tested for their ability to withstand other types of pressure. Fortunately, although wood-pulp byproducts might not sound particularly hardy, the bio-based resin materials used in these homes is nothing to sneeze at. In fact, Dagher pointed out, the materials are significantly stronger than concrete in compression.
“These materials have compression strength between 8,000 and 10,000 psi,” he said. By comparison, standard concrete has a psi of about 4,000. Interestingly, the walls of the bio-home are easy to work with and permit drilling in order to install kitchen cabinets, for example, despite their “excellent compressive strength,” Dagher concluded.
“The other advantage of this type of construction is that you can easily change the thickness of the walls and roof trusses and the space for installation of insulation to accommodate different climate demands,” Dagher said. He noted that earlier this year temperatures around the model bio-home reached a wind chill of -45 degrees Fahrenheit.
“It really exceeded our expectations of a ‘good old Maine winter,’” he laughed, noting, “We saw no issues. There were no cracks in the walls or difficulty controlling the temperature inside. In fact, inside, it was very comfortable, nice, and warm.”
A Dynamic Solution to a Pernicious Problem
The model home’s resilience under winter pressures is a promising sign for the project for more reasons than just keeping residents warm and toasty. Because bio-homes can be printed anywhere, packed with insulation and pre-strung with wiring, then transported in one piece to a slab in the location of the owner’s choosing, they are an ideal fit for regions like Maine where the construction season is seasonal and short.
“Our vision for these homes is that we will have much more flexibility on the construction period,” said Bird. “You can see the possibilities when you could put down your concrete slabs while the weather is amenable, then have multiple homes printed and delivered on a large scale regardless of outdoor temperatures.”
Because the bio-home needs little more than a slab upon which to rest, the placement of the property is highly flexible as well. This means that the Penquis development is likely to highlight existing natural features, green space, and current geography more than other developments of this nature typically are able.
“We have the flexibility to do that because once they are delivered, the crane can place the bio-home in the exact spot we desire,” Bird said. Penquis hopes to create more of a “community structure” in the neighborhood layout thanks to the additional design and development flexibility.
The printing process also allows for more customization and refinement of the interior of the buildings as well, something that has long presented serious obstacles to creating appealing affordable housing options on a realistic budget.
“The trade-off we struggle with in affordable housing is that we do not want to just build boxes or utilize substandard designs just because that is the only thing that fits in the budget,” Bird explained. “This technology allows for craftsmanship and unique ways of designing living space that has not previously been afforded housing of this type and offers a way to make low-income homes differently than we do today, be cost-competitive, and use green, renewable resources to do it,” Gilman concluded. “We are proud that this first home is already such a comfortable place to be, and we have been thinking about livability since the beginning of the project.”
Side Bar 1
“Bio-Multifamily” Possibilities Loom Large
What’s more exciting than a single-family residence “printed” using 100% recyclable materials that are strong enough to withstand sub-zero temperatures and hurricane winds, flexible enough to permit wild design freedom within the living space, and groundbreaking enough to permit installation almost anywhere?
For someone like Jason Bird, executive director for Bangor-based housing-focused community action agency Penquis, the answer is a multifamily residence with all the same advantages.
Penquis has been working closely with the University of Maine’s Advanced Structures and Composites Center (ASCC)’s research team for quite some time now, diligently working to figure out ways to print single-piece, prefabricated homes that function like carbon locks in terms of environmental friendliness and look like something out of a design magazine. Meanwhile, Bird focuses on optimizing the units for maximum livability.
“There is so much potential around this product because of the amazing structural stability and customization of interior space within what could easily someday become ‘building blocks’ for a multifamily building,” Bird explained. “We expect that soon we will be able to print kitchen cabinets, bathtubs, and other elements that could dramatically impact the amount of time it takes to build these homes and how much it costs to do so.”
Both single- and multifamily options could play a major role in resolving the stubborn and ever-burgeoning housing crisis. “The homes themselves are extremely exciting, and so is the technology that will emerge as we continue to go forward,” Bird said.
Side Bar 2
Investing in the Future at Top Speed with Bio-Homes
Although Penquis has already gotten on board with the first bio-home development in history thanks to its nine-home order that the organization hopes will be on the slabs and available to residents in just two short years, it is not too late for other investors to team up with the University of Maine’s Advanced Structures and Composites Center (ASCC) to print out bio-home communities.
“Ultimately, our goal is to print out one of these homes every 48 hours,” said Habib Dagher, ASCC’s executive director. “Currently, we are working on scaling up processes and essentially creating a factory and design environment for these homes. One we prove that out, it will be the right time to take this out into the private sector.”
Because of the unique sustainability of the bio-homes, these types of projects may qualify for combinations of funding that might not otherwise be available to investors and developers. In the Penquis development, funds have been provided from both public and private sources. Dagher noted that part of proving out the uses for these homes includes seeing how the first models react to different environments. That means there is an ongoing need for future demonstration neighborhoods in different parts of the country.
“Anyone who wants to know more about how they can be a part of that, well, we are happy to talk to them!” Dagher said.
Learn more about the Advanced Structures and Composites Center and the bio-homes project at Composites.UMaine.edu/biohome3d.
