I had heard about BONE Structure through a few different sources, but had yet to take a tour of the facility until recently. Marc-André Bovet, President of the company, took time out of his busy day to explain to me what BONE Structure is all about. BONE Structure is not a prefab home company, but rather a different way of building residential spaces.
Marc-André told me that there were always a few things that bothered him about the residential building industry:
- The amount of waste produced. In a typical residential construction, three dumpsters will be filled with leftover waste that will end up in landfill. In fact, he told me that 60% of all landfill is due to construction waste.
- Time it takes to build a home. An efficient contractor will probably be able to build four good houses in a year using traditional “stick-build” method (ie., 2x4s and 2x6s). Many interior finishes such as built-in cabinets, kitchen cabinets etc., have to be ordered only after the actual walls have been built, which can add months to a job. Floors, especially those with radiant heat take days to install because the concrete needs to be poured and leveled before the tubing can be installed.
- Human error. In every home build there is always the possibility for error. Window heights are mis-measured, bathtubs don’t end up fitting perfectly in the corner for which they were designed, the insulation used is can be different than the insulation specified. Kitchen cabinets can’t be ordered until the kitchen has been drywalled, because what the house plans dictate and what is actually constructed are often two different things. It’s rare for plans to be followed exactly as written by the designer or architect, and this can create a whole list of problems. In fact, Marc-Andre told me that up to 80% of all trades are unable to read architectural plans.
- Mold, Mildew, Rot: If buildings aren’t sealed properly, water and air can find their way into homes causing mold and mildew. If the mold is black mold it can lead to respiratory problems in children and older adults who live in the home. Rot can affect the stability of the house, leading to a home’s shorter lifespan.
Marc-André set out to develop a building system that solved these problems. He took teams of engineers to different places (including aerospace engineers), designers and architects, searching for solutions to the building problems he’d identified. Then, one day, it came to him: in the automotive and aeronautical industry better materials had developed along side design and technology. Wood was used for the first horse-drawn carriages and for some parts of the first cars, even the first small planes. But as each industry progressed, wood was abandoned for steel, carbon-fiber, aluminum and lighter weight, more durable materials. Why hadn’t the same thing happened in the building industry? Why was steel used for skyscrapers but not houses?
So, light gauge steel became Marc-André’s building material of choice. Then he decided that homes should be as easy to construct as Lego; that precision in the building pieces would lead to better, more secure buildings. On top of that, sending exact-sized pieces to a job site meant there was zero waste — no off-cuts were necessary because the parts were measured and made to precision at the factory. It also keeps a job site clean and tidy and keeps dumpsters off the site too.
Marc -André and his engineers designed a system that clips together in a precise way, and it all starts with the foundation. The system is self-correcting; there is no way any piece can be slightly off-kilter because they can only fit together if the system is straight — which is why BONE Structure takes care of pouring the foundation. Steel struts are clipped in place, then bolted together in pre-drilled holes. No extra drilling is required on site. In fact, all you really need is an electric screwdriver. No saws, measuring tape, glues, adhesives, etc. It also keeps the job site clean and tidy.
Another goal of BONE Structure construction is to make it as easy as possible for the installation of plumbing, electricity and HVAC systems, so all of the struts are designed with spaces for all of the equipment to be installed. Electricians and plumbers have no need to drill any holes, light switch boxes are hung on horizontal struts and can be moved anywhere along the strut to suit the electrical plan.
Once the steel structure has been erected, SIPS (structural insulated panels) are used for the roof and insulating polystyrene panels are added to the walls for insulation. The entire building is then coated with PolarFoam/Heatlok insulation (I’ve written about its benefits before), wrapping the building in an airtight envelope with only the doors, windows and HVAC holes providing any thermal bridging (heat escape) through the envelope. The final insulation of the building: R-28.5 for walls, R-56 for roof. Estimated time of construction for building the exterior structure: 5-15 days depending on the complexity of the design. The interior finishing can also move along at a good rate. Because there is no need to drill holes for plumbing, HVAC and electrical units, contractors spend 30% less time on a job. Me, being the skeptic that I am, asked “How would you know if you are being charged more hours than it takes sub-contractors to do the plumbing, electrical or HVAC job?” Marc-André responded that for certain designs, they’ve produced enough houses by now that they know approximately how many hours electrical/plumbing/HVAC installation will take. “If your contractor estimates more time than our numbers on past [similar] jobs have shown, we’d suggest you get another estimate.”
Indoor Air Quality: No rot, no mold, no mildew. Because the structure is made out of steel and not wood, and because it is sealed with an envelope of spray foam insulation, there is no chance for mold or mildew to occur due to the structure of the building. There are also no glues or adhesives used in construction of the envelope so no chance of off-gassing. (Note: However, it is important to be aware that while the building won’t off-gas, any flooring, fixtures, built-in cabinets and furniture that a client brings into the space, could possibly off-gas. If indoor air quality is important to you, make sure low and zero VOC products are used, or look for “Greenguard” certified products for use in your home.)
Transportability: the structure is shipped as struts which are assembled on-site (think of Meccano). Because the truck is an ordinary flat-bed, roads to remote areas can be narrower than those demanded by some types of modular homes. There is less disturbance to the area around the home.
Design: Because of the way the structural struts work, architects have a vast amount of freedom of design. Living spaces can be as large as 25×25 feet without needing load bearing walls or bulkheads. Marc-Andre told me that the residences their architects design tend to have a smaller overall footprint than clients thought they originally needed because so much can be done with a 25×25 foot living space and high ceilings. Here’s the other great thing about this design: while BONE Structure has two architects in the firm, clients can also use their own architects and interior designers if they choose.
Cabinetry: Kitchens and built-ins can be designed and built at the same time as the house because wall measurements will be exactly as specified in the plans. BONE Structure also introduce their own kitchen line last year. Drawers and cabinets are made of solid maple (no melamine cabinets, means no chance of warping), with soft closing hinges.
Environmental features: While the structure is made out of light gauge steel with 40-60% recycled content (which is also 100% recyclable at end-of-life) and Heatlok spray foam for the insulation (one component of the spray foam is recycled plastic water bottles), the company does not focus on green features per se. While you and your architect can design in solar thermal and photovoltaic panels, a gray-water system, low-flow fixtures, maximize passive solar in winter, etc., the main features of this home are its durability, tight building envelope and lack of waste during construction. Because its bones are made of steel, its life expectancy is predicted to be, well, Marc-André couldn’t give me an exact amount of time because it stretches too far into the future, but you can bet these homes will be there for your grandchildren, great grandchildren and beyond.
Financial efficiency: because these homes take less time to build, there’s less bridge financing, (if needed), and less money spent on living accommodations elsewhere while waiting for it to be built. From the builder’s perspective there are fewer trips to the site for installation of everything from plumbing to radiant floor heating. Contractors will recognize that this type of structure will give them the opportunity to build more homes in less time, while building a quality home which needs very little maintenance after it’s constructed.
Cost: When I asked Marc-André what the cost per square foot was of a BONE Structure building, he said quoting that way is difficult because so much depends on what kind of finishes you use, where you’re building, how many and what kind of windows and doors you install, etc., but he said that generally, a BONE Structure house with high quality interior finishes would come in around $200 per square foot. Then he told me that they’ve just launched a new model home, C-007, a 1329 square feet, turnkey, for $279,000 (featured above). While the price doesn’t include land, it does include the cost of pouring the foundation — assuming there are no structural challenges involved.
BONE Structure is a method of building homes that has the opportunity to revolutionize the residential building industry. Homes go up faster than traditionally built homes, they are more durable; mold and mildew resistant, and, finally, because the main component is light-gauge steel, homes are seismically rated.