Loblolly House: In Stock and Ready to Ship

Of all the names to give a house, only an architect would settle on the knotty word loblolly. Never mind that the house’s spectacular site spills onto the wide-open Chesapeake Bay, with a rough cyclopean wall of coastal riprap keeping the water averted; the architects were instead inspired by the pine trees blanketing the grounds, which have the fortune of possessing an unforgettably boisterous vernacular name.

An unlikelier setting—Taylor’s Island, Maryland—for an experiment in prefabricated housing perhaps could not be found, but the glorious site for Philadelphia-based KieranTimberlake Associates’ Loblolly House is intended to serve just this purpose. Although years in planning, at press time the three-bedroom, two-bath, 2,200-square-foot house lacked only a few finishes and final landscaping after an on-site construction period of less than a month.

“We didn’t know fully what we were going to get into with this project,” says Steve Kieran, FAIA. “But we knew we wanted this to be a complete realization of a way to build more like the automotive or aviation industry.” Kieran, along with James Timberlake, FAIA, laid out a fundamental philosophy of architecture production in their 2003 book, Refabricating Architecture (published by McGraw-Hill), which focused on building supply chains, prefabrication processes, and rediscovering the role of the architect as a master builder capable of singularly overseeing all aspects of design and construction. Both architects view Loblolly, designed as a second home for Kieran’s family, as an opportunity to test the theories of the book without needing to convince a client to pay the bill.

KieranTimberlake’s Loblolly House mimics the surrounding pine trees in its raised structure. Images: Courtesy KieranTimberlake Associates, except as noted

Refabricating history

Failed prefabricated, or modular, housing projects pepper the history of modern architecture. Although early Modern architects embraced the spirit of the mechanized world, the buildings they designed mostly reflected the spirit of the age (think of the mechanized surface aesthetic of early European Modernism) more than they physically provided its solutions. In the realm of residential design, Buckminster Fuller’s 1927 Dymaxion House—the first and perhaps reigning champion of humbling attempts at universal prefabrication—remains a touchstone for architects anxious to incorporate the streamlined production techniques and one-size-fits-all mentality of manufacturing into a building industry that has remained relatively unchanged in the past hundred years. Writing in Arts Magazine in October 1963, Reyner Banham called the Dymaxion a “radically new environment for domestic living” that parlayed Fuller’s penchant for technological “hot-rodding” into a design concept the world needed: an energy-efficient, mass-producible modular house suitable for any site. Among the other few successes, Carl Strandlund’s 1947 Lustron House—prefab steel homes with exterior porcelain-enamel-coated panel cladding—achieved some acceptance, with nearly 2,500 built prior to the developer’s 1950 bankruptcy. While other stunted projects come to mind—Albert Frey’s 1930 Aluminaire House or Matti Suuronen’s wacky, bubblelike 1968 Futuro Houses—interest in Modern prefab residences waned until a resurgence in the 1990s spurred in part by the public’s rediscovery of Midcentury Modern design, digital and technical advances in mass-fabrication techniques, and the promotional effects of consumer publishing, most notably the cheerleading Dwell magazine.

In his essay, “The Great Gizmo,” in the September 1965 issue of Industrial Design, Banham neatly summarized the progressive objectives of American industrial initiative embodied in prefab: “They do not require high skill at the point of application, they leave craftsmanship behind at the factory.” While nearly all Modern prefab houses—particularly those so recently in consumer vogue—share this ambition of realizing standardized components, wide application and adaptability, and quick assembly, few designs have achieved extensive implementation. Experiments in mass-customization of housing by the federal government, such as George Romney’s 1970s programs as director of the Housing and Urban Development agency, fell apart when funding evaporated. The grand exception to these trials, of course, clogs highways from coast-to-coast: flat-bed, truck-mounted, factory-built “traditional” homes designed to meet the hauling requirements of the Interstate Highway System. Lately, these units have achieved a certain dreaded notoriety as so-called “Katrina houses.”

From the outset, KieranTimberlake Associates (KTA) resisted such conventions. Instead, it was intent to realize a hybrid version of prefab with flexibility in its design to permit a variety of floor plates and programs, even perhaps to eventually find use in commercial and multifamily housing projects. It’s not a new house the architects were after, but rather a new production process for architecture or, as they argue in the book, a transformation of the architect into something akin to a process engineer. “There is no incentive to change,” Timberlake says. “But, like the car industry, architecture and design will eventually develop a product that works anywhere in the world. At least, it’s good to dream that way.”

Not your father’s prefab

KTA’s Loblolly departs most wholly from past prefab models through its innovative component-based design, in which KTA minimized the number of parts. “We want materials we can take apart like used auto parts, as opposed to ending up with rubble,” Kieran says. Unlike many houses, even those built with sustainability in mind, Loblolly’s components, or elements, as the architects call them, could be unbolted and reconfigured at another site for a different house or, as the architects like to demonstrate in their public lectures, sold off in pieces on eBay.

Green roof Cedar cladding panelized Prefab boxes for bathroom and kitchen Prefab coffer floor system Structural pilings Double west wall skin Bosch Rexroth structural aluminum frame

Steve Kieran says the entire Loblolly House fit on two tractor trailers for delivery to the site. The architects reformulated typical house design into larger elements that combine a variety of CSI building materials into simple units, such as floor cartridges, that could be easily installed in the field.

Both Kieran and Timberlake credit the advances made in digital parametric modeling for enabling the project to move forward. Created in AutoDesk’s Revit, one of the most widely used building-information-modeling (BIM) programs, Kieran says the software provides a previously unattainable level of certainty. “We had a new depth of control and a new depth of specificity, geometric certainty, and three-dimensionality, where we could just order materials directly without going through a shop drawing process,” Kieran says. He is still somewhat amazed that he could sidestep one of the more time-consuming, paper-wasting jobs of the contemporary architect. This precision in design entitled the architects to divide the house into a series of major elements: uniform “cartridges” for floors and walls; a standard, off-the-shelf aluminum structure; uniform exterior rain screen cedar panels; and factory-built bathroom and kitchen modules.

These elements fuse, in design and specification form, the Construction Standards Institute (CSI) divisions architects and consultants typically use. Kieran and Timberlake both feel the CSI divisions limit the possibilities for the integration of building components. “CSI doesn’t disappear, the products still exist,” Kieran says. “They just aren’t isolated any longer, they’re integrated.” But for this to work, the architects needed to establish a new framework for how each conventional material would then be combined into the unconventional elements used in on-site assembly, while also identifying the party responsible for the work—be that the on-site contractor or the prefab assembler.

 

The supply chain gang

Drawing directly from its book, KTA set about early in the process creating a supply chain of materials and products that could feed the assembly line of elements that would constitute the house. Timberlake considers this the most difficult aspect of the firm’s attempt at true prefabrication because, he notes, the “construction industry is so fragmented, with no control of the supply chain and new suppliers starting up every day.”

The architects divided the chain between three tiers of suppliers and a final assembler, much in the way automotive companies outsource major components of each car with final assembly at factories throughout the world. In the case of the Loblolly House, Bensonwood—a New Hampshire–based timber-frame-house company—acted as both a supplier and the final assembler. Bensonwood recently completed a quasi-prefab house as part of the Massachusetts Institute of Technology’s Open Prototype Initiative, which streamlines a design-build approach for high-quality custom houses with quick construction schedules. Bensonwood, as well as a construction manager, Arena Program Management, collaborated with KTA to devise the specifics of the supply chain for Loblolly.

The architects developed a comprehensive building information model (BIM) using the Revit software program. The model enabled them to precisely order the aluminum frame (above and below).

Marilia Rodrigues, a project architect for KTA, helped develop the supply chain, which then fed her work on the virtual model within the Revit software program. Before it became ubiquitous, KTA adopted parametric modeling into its practice after finding inspiration from a 2002 trip the architects took to Boeing’s facilities in Everett, Washington. This led to initial development of the Loblolly House on an early version of Revit. KTA’s conversion to BIM hasn’t been easy; as Timberlake says, “Having learned to draft with a T-square, the hardest part is learning how to work through the fingers and palms of others.” Still, both Timberlake and Kieran feel so strongly about the need to evolve their practice, they require BIM to some degree on all projects.

Toward the beginning of the project, the team settled on an extruded aluminum frame structure manufactured by Bosch Rexroth and typically used in factory and temporary structure applications. Knowing the exact specifications of the structure enabled Rodrigues to build a true virtual model with a design tolerance of only a few millimeters, an impossible feat with conventional materials like wood or steel. “With the model, we see the house as existing,” Rodrigues says, which then allowed KTA to order finish items and casework directly. “It’s amazing how much our industry relies on that final field measurement, which we didn’t need.”

The model enabled them embed supply-chain information regarding other materials, such as the exterior cedar siding.

Bosch never intended its frame system for architectural use, so KTA developed a collection of five connectors that would meet the structural requirements of a three-story house with its requisite dead, live, and wind loads. While the connectors were expensive to develop (KTA is pursuing patents for its designs), the frame system’s reliable measured precision of a 1-millimeter tolerance and the fact the frame could be constructed on-site in a few days won the architects’ favor. Even with advanced techniques in computer-enabled steel fabrication, only aluminum, with its silicon-based alloy blend, can achieve this precision without the need for shimming in the field—more than offsetting any cost differences. Additionally, the frame system’s grooved channels connect to cartridges, windows, and sliding doors through the use of T-blocks (2,100 in all), which screw the house together.

KTA embedded supply-chain information in the Revit model, so a click on any framing element or finish material displays, such as dimensions, material, and supplier—effectively combining design and specifications into one digital locus. The architects converted the model into AutoCAD, which allowed Bensonwood to convert it into its fabrication software, CadWorks.

“It’s elementary, my dear” architecture

The Bosch frame sits on pilings that were put in place over three days in February 2006 during initial site work. According to Chip Arena, the construction manager, the site needed extensive stabilization, since it’s almost a marshland in consistency. Soggy grass notwithstanding, the exposed waterfront site explains why the Loblolly House stands on pilotis, though Kieran says hurricane-style flooding is extremely rare on the island. Arena oversaw site utility work, as well as construction of the timber frame connecting the pilings as a base for the Bosch system.

Microduct air supply Engineered lumber ribs Radiant heating coil Plywood sheathing

Each smart cartridge (above) for the floor contains building systems that terminate at connectors, which then tie into main service channels on each floor and back to mechanical-room blocks, where the systems “quick-couple” into supply units.

The site, a fragile ecosystem and one of the best places in the country to see bald eagles, benefited from the fact that little area for storage of materials or for staging was required, as elements arrived on-site in a just-in-time-for-assembly manner. The project’s swift construction schedule began in late September; on October 4, for example, during a site visit by Kieran, assemblers from Bensonwood unloaded and, with a small crane, placed the roof on the house in nearly 20 minutes. (Kieran intends to plant a sedum green roof in the spring.)

click images to view them larger Cartridges, as well as blocks, were fabricated in a New Hampshire facility (above left and middle). The extruded aluminum frame (above right), has a precise tolerance of only 1 millimeter.

The roof and floors consist of 19 cartridges, which were the main elements fabricated in New Hampshire by Bensonwood and by far the most complex technological innovation of the house. KTA segmented the cartridges into two types: smart, containing radiant heating pipes, electrical distribution and outlets, cooling microducts, and insulation; and dumb, containing only insulation. Both types of cartridges basically consist of standard sheets of plywood (to ease construction and maintain the modular nature of the elements) sandwiched together with conventional wood two-by-fours. The cartridge design also allows access areas for future maintenance.

Wooden base frame and pilings in place Aluminum frame, first floor, and utilities modules added All floor cartridges in place The house as it appeared October 4

The smart cartridges, used exclusively for the floor, have utility “whips” that tie into a main supply channel on each of the two occupied floors of the house, eventually connecting to mechanical rooms on either end. The mechanical-room blocks, as well as the bathrooms and kitchen, arrived on-site fully framed and nearly finished, moved by crane into place to await final connection. Dumb cartridges make up the exterior walls and hang so the aluminum frame remains on the interior to prevent exposure to moisture. Cement board attached to the exterior face of the cartridges seals the house, while a varied pattern of cedar boards agglomerated into units clip onto the frame, acting as a rain screen and aesthetically nodding to nearby loblolly pines. On-site contractors will fill in gaps from the prefab process, such as putting down the green-dyed bamboo flooring in the main living areas and ceramic tile in the bathrooms. (Bensonwood declined to do both finish items in its shop because of shipping concerns.)

Bensonwood, best known for producing and erecting residential timber frames, but not the houses themselves, retooled its assembly line to fabricate the cartridges and the modules. Hans Porchitz, Bensonwood’s project manager, says once he and his colleague’s understood KTA’s ambition, as well as the details of how every component would interconnect, production of each element went from raw wood stock to finished material with a click of a button as the CadWorks model directly fed the company’s computer numerical control, or CNC, machines. Bensonwood’s fabricators, as well as subcontractors, like electricians and plumbers (a first for the company), then assembled the materials into the elements for final delivery.

Putting it together

For Bensonwood, the pinch points of the project occurred at the connections of the frame, elements, and systems. “There was no standard, nothing in the book you could use,” Porchitz says. “That’s really something missing in the construction industry as a whole.” Each element, from the aluminum frame to a cartridge to a module, received a bar code (tracked within the Revit model) so that on-site assemblers knew exactly where to install them.

Aside from the aluminum frame connectors, the house uses an innovative system of electrical plug connectors that qualify under codes as junction boxes. This “quick-coupled” system allowed each cartridge’s whip to plug into a main electrical channel that could then be plugged directly into the house’s electrical panel, making field connections foolproof. Flexible radiant heating and domestic water tubing connects at a wall of manifolds in each mechanical room; heating is thermostat-controlled based on each room’s environmental needs, but the manifolds also enable manual operation. The microducts, which Kieran says he included at his family’s request, since the marshlands can get sticky hot in the dead of summer, also tie back to the mechanical rooms to small air-handling units.

Loblolly House, pictured above on October 4, was completed last month. Photography: © Russell Fortmeyer

Although the house incorporates heating and cooling systems, the architects designed the entire west wall to open in various stages to the outside, in order to, as Kieran says, tune the house to shifting environmental conditions. A NanaWall system of glass doors provides environmental isolation, while an exterior-mounted, overlying aircraft-hangar-type door system acts as a separate bifold shading device, entirely electrically operated. The house’s appearance—three closed sides and one entirely open—encourages Kieran to refer to Loblolly as a “duck blind,” one of the ubiquitous hunting accommodations scattered across Taylor’s Island.

The other comparison Kieran fondly makes is that of a barn raising, but few barns pack this technological punch. Unlike the garbage heap of unsuccessful prefab experiments of recent decades, which, in Kieran’s words, failed to understand the need for predictable, standardized components and connections, the BIM model of Loblolly has proved effective in pulling a theoretical prototype together. “As soon as you get materials out in the field and they don’t fit, you’re into handwork, and then you might as well have done the whole thing by hand,” Kieran muses. “That problem is gone.”