H. H. "Hoot" Haddock
The offices of IHSN are in an unassuming prefab office building just north of downtown Florence. It's not all that easy to find (I couldn't make out any street numbers from the road), and the signs make little attempt to stand out. I drove past it and had to backtrack. Once I found the right parking lot, the "ThermaSAVE" sign pointed out the correct door.
The inside is as plain as the out. When I arrived, "Hoot" was on the telephone. His office was a long, narrow space with tables on both sides. A gray electrical box full of switches and wiring sat on one, obviously a work in progress. In addition to being the CEO, he's also the company electrician; he builds the electric components for their machinery.
....
I could expand on my notes on his test specifications, materials samples, pre-applied and optional finishes, the factory and his test jigs, but those aren't really important. What's important is the essence of what he's offering: the ThermaSAVE Structural Insulated Panel (SIP).
What makes ThermaSAVE such an accomplishment is what it can do. SIPs have been around for a while, but they've always had their limitations. Many are made using materials which are vulnerable to water. Others lack insect resistance. Some are not self-supporting and require other framing such as post-and-beam, adding cost and reducing architectural flexibility.
Haddock started with more or less the same techniques as everyone else, but he never stopped making improvements. Through Edisonian persistence he has managed to come up with a system which eliminates all of these flaws, and quite a few others.
The stock ThermaSAVE panel is a relatively simple affair. It is made of two cellulose-reinforced cement skins over a core of insulating foam, usually styrofoam beadboard. Selection of glues, priming paint for the skins, and other details determine the outward qualities. The mating edges of the panels have slots cut into the foam adjacent to the skins; cement-board splines fit into these pockets and bridge the inter-panel gaps, allowing them to be connected together with screws to make walls, floors and roofs. Slightly oversize foam is compressed when the joints are closed before driving screws, sealing the joints against infiltration of air and water. Once assembled, the finished surface presents nothing to the world except screw heads and the cement board. There is nothing to burn, making it effectively fireproof.
A sufficiently thick panel makes a very strong beam. One picture on the company website shows a pickup truck parked atop a panel which has one end supported in mid-air. There is not even any visible deflection. It is obvious that these panels are very strong.
The unseen parts are just as important. The connecting splines run parallel to the faces; there are no breaks in the foam from one skin to the other, no thermal bridges to allow heat to short-circuit the insulation. Priming paint and the proper glue prevent infiltration by water. A dose of boric acid in the beadboard and the cement of the skins makes them unpalatable to insects, as well as lacking in nourishment.
A sample of a ThermaSAVE panel rings when struck with the knuckles. The impression is that the panel skins would be brittle. They are anything but. Screws driven less than an inch from the edge of a panel create no cracks. The high-frequency ring and the ability to support light trucks without deflecting betray the panel's chief virtue: it is extremely stiff. In addition to being very strong, it is very hard to deform. The panel skins would bow under a relatively small pressure, but once fixed to the foam core they would have to either break free of the foam or crush it in order to move.
Why's this important?
Most buildings are limited by buckling strength, not tensile strength. A structure which buckles can collapse without breaking. This is why tall towers have guy wires: the wires add to the compression stress on the tower, but they also prevent it from failing by buckling to the side. The greater the stiffness, the more force it takes to cause buckling.
Conventional wooden construction falls down by degrees. The ridge beam sags, the tops of the walls bow outward, and the roof's rectangular shapes acquire curves at the peak and eaves. This progressive bending pulls out fasteners and splits the wood they hold. External pressure, such as from a strong gale, can cause similar deformations inward. Either one can lead to total failure, as the structure comes apart at the joints.
This appears to be close to impossible with a ThermaSAVE structure.
The virtue of this construction method is that its surfaces are made of very stiff panels, connected rigidly with splines. All the components can still break; however, it is extremely hard to make them buckle. Each wall, floor or roof forms a continuous shear web. The roof cannot slump in the middle; any forces pushing toward the eaves are transferred across the width to the gable-end walls, which they push parallel to the surface rather than outward. The gables can't move without racking the eave walls into parallelograms, which resist with far greater stiffness than 2x4's and plywood ever could. And the eave walls can only deflect the tiniest fraction of an inch without either racking the roof above and floor below, or breaking loose from them.
The last innovation made this a lot harder too. Conventional lumber is strong, but it splits when overstressed. The ThermaSAVE panels do not need lumber for strength; all they need is a solid material which holds fasteners securely. This allows wooden base and top plates to be replaced by plastic lumber. Plastic holds screws much better than wood, and it has the virtues of being waterproof, mold proof, rot proof and unpalatable to bugs. Last but not least, it does not require cutting a single tree (and may even be made from recycled materials).
There are still improvements to make. Wiring is an issue, for one thing. The current scheme creates internal wiring channels by cutting small troughs in the foam below the inner panel skin (done with a hot-wire cutter before the panel is glued together); after holes have been cut for junction boxes, cable can be fished through the passages. The problem is that the wiring remains next to the surface, and vulnerable to nails and screws. This is likely to be prohibited by electrical codes in many places. Many codes require wiring within screw-range of a wall surface to be run inside conduit. Perhaps panels can be made with steel U-channel to cap the wiring troughs, increasing the difficulty of hole-cutting but armoring the wires against the errors of handymen.
The energy impact
Of course, this would mean little if buildings made from it cost too much to keep habitable. ThermaSAVE lives up to its name. Styrofoam beadboard is roughly R-5 per inch; a 5.5-inch core is R-27.5 almost throughout, being reduced but slightly at panel joints and bridged only at junctions of floors and walls. Thicker panels are both better insulated and stronger; a 12-inch panel would be in the neighborhood of R-60.
"Hoot" cites the example of an office building he'd built. The occupants had used it through the summer and fall, and finally shut down over the December holidays. Upon their return, the building was cold. They checked the heating system, and found that the installer had never hooked it up; the building had needed no heat beyond the occupants and equipment!
What does this mean for us?
It means that the zero-energy building can be made today. It can be made from common, inexpensive materials, put together with little labor. This building will resist attack by water and mold, has nothing to attract beetles or termites, and will not support combustion. It will require little money to maintain and little or nothing to heat. It will shrug off earthquakes and be easily repaired even if flooded. It is likely to be the last thing standing in the path of a tornado. It might even be inexpensively engineered to weather most other natural hazards.
It means the threat of "freezing in the dark" moves a long ways away. So does the prospect of a housing collapse driven by a lack of heating fuel. These threats will stay away through extremes of weather and ruptured faults.
In short, this material — this building technology — looks like just the thing to future-proof our building stock.
How this affects the economy and environment
Buildings account for more US carbon emissions than vehicles do. The monetary cost is lower because the fuels (natural gas for heat, gas and coal for electricity) are cheaper than oil, but the price is still substantial and growing with time. Collapse scenarios such as Kunstler's hinge upon a fuel crisis making it impossible to keep the building stock habitable. A rapid increase in building energy efficiency would address all these issues. Cutting the energy required for a building reduces the cost of running it. As the required energy decreases, shortages become less and less likely. The reduced energy input cuts the amount of fuel needed to supply it, and the emissions of carbon and conventional pollutants shrinks. Cutting the energy requirements makes all of the associated problems smaller and more manageable. ...
The rest:
http://www.theoildrum.com/node/2933