A catalog of non-toxic building systems.
Sunday, June 26, 2005T-Slot Framing - Factory Automation Comes Home
This is one very promising type of construction system the author extensively studied and at first had abandoned for practical housing use. But recently introduced products have changed things, making this not only practical but perhaps one of the most sophisticated of all building technologies currently available.
Extruded aluminum T-slot framing was developed as a simple modular building system for use in laboratories and factory automation where it allowed for the quick design and assembly of support structures, enclosures and cabinetry, custom furniture, and various mechanisms. T-slot gets its name from the 'T' shaped slots which are formed in the sides of otherwise square or rectangular extruded profiles. These allow for the connection of pieces using special T-nuts and other fasteners as well as the attachment of an infinite assortment of specialty components. The slots also allow for the mounting of glass or opaque panels, grills, and screen in the slots, sometimes using rubber gasket inserts.
The virtue of T-slot over previous modular frame systems -such as Box Beam- is that it allows for the in-line attachment of frame parts so they need not overlap each other or get in the way of components attached to the edges of the frame. This allowed for much greater versatility and simpler design, although the T-slot profiles are more elaborate to manufacture and much more expensive. T-slot, because of its hollow core, also allowed for the integration of pneumatic components using the frame members as pressure supply lines. This made T-slot ideal for the construction of simple custom robots and automated machinery and a vast assortment of T-slot components just for that application have evolved. Though T-slot seems generally unknown to the average person, quite a lot of the goods we use daily went through machines made out of this.
Because it is made of aluminum, this author considered T-slot a logical choice for use in DIY non-toxic housing. Aluminum is largely inert, perpetually recyclable at a lower energy overhead than steel, needs no painting or other protection, and the components are light and assembled with simple hand tools needing no special skills so that even someone with diminished health -like most MCS patients- could manage some degree of sweat-equity. And its as easy to dissemble a T-slot structure as it is to assemble it, affording it the virtue of perpetual demountability and structural adaptation. This was potentially the most sophisticated means of home building available -a platform for a true plug-in architecture. But there were a couple of critical problems with it. Though it has been used in a supplemental role architecturally, the small dimensions of the typical T-slot profiles made it difficult to use for whole building structures. One had to either build trusses from it, build framing akin to conventional stick framing, or buy 'combination' profiles where the smaller profiles are bound together and filled with foam to make beams and posts of large size. All of those options were prohibitively expensive because the number of parts was so high, and compared to lumber of the same dimensions, T-slot is many times more costly. What was needed was a very large dimension T-slot profile -6" to 12" square- that could be used for the primary components of simple post & beam box frames. But no one made this. The manufacturers of T-slot had never encountered a demand for such large profiles and had never seriously considered the use of their product for construction.
However, this year (2005) things changed with the introduction of two architect-designed modular home products based on brand new large dimension T-slot profiles. One is called Tomahouse and the other the iT House. Products of the current Modernist Pre-Fab housing craze, these ultra-Modern kit homes finally realize the potential of T-slot framing for construction, using simple pavilion designs based on simple post and beam structures just as this author had previously imagined. Somehow the designers of these homes managed to do what this author could not; convince T-slot makers that there was a point to and market for housing made from T-slot profiles.
Of the two the Tomahouse is the more sophisticated in that its designer has developed a modular home system with interchangeable components and a core pavilion module which is combined in various ways to produce homes of any size. The iT House is more concerned with a single one-size-fits-most minimalist home design that is pre-fabricated and marketed like a single large appliance. Though their designs hint at it, they do fall short in realizing the potential of T-slot as the basis of a plug-in architecture.
The basic idea behind plug-in architecture is that the structure of a home is a standardized modular 'backplane' akin to the backplane or motherboard of a personal computer. The objective is to not simply produce one or two clever designs but rather to cultivate a vast catalog of diverse components made by innumerable manufacturers that directly integrate into this backplane like the plug-in expansion components of a computer and can easily be installed and removed by the end-user/home-owner himself with no special skills necessary. For instance, wall, floor, and ceiling panels could be complete integrated appliances including TVs, home computers, kitchen and bath appliances and fixtures, heating, etc. The potential for built-in furnishings is unlimited. These would be simple modules that a home owner can himself plug-into the basic frame of the house with simple tools much as he does adding a new peripheral to his desktop computer. This is what T-slot has very successfully done for the industrial automation and laboratory equipment markets. It can do it for housing too, if one is clever enough to realize it. At the moment, though, only these two design companies are doing anything for housing with this technology. None of the innumerable manufacturers of industrial T-slot add-on components have caught onto this idea.
As the basis of non-toxic housing, since these two kit home products are still the only places one can obtain these components they are the only off-the-shelf option. Luckily, both of them are pretty low-toxic as-is and could be easily made fully non-toxic with a few minor substitutions in finishing materials. The Tomatek company seems the most amenable to this notion. The designers of the iT House are very fixed on their one and only design and are likely to be less flexible. Both are modestly priced, though still rather expensive for the typical MCS patient. If competition should develop in the future and more manufacturers wake up to the market potential, the price of these may decline.
