Documenting a personal quest for non-toxic housing.
Wednesday, May 14, 2003Ideas and Project Update - A place to park your caboose
I've been studying an intriguing concept for creating a pavilion style home by reusing an off-the-shelf product. Most architect designed Modernist pavilion homes have had surprisingly simple structural systems, this being a significant aspect of their minimilist aesthetic. These have generally been simple box frame systems with flat or low slope roofs essentially the same as that employed in any commercial building, and often based on the same kinds of components such as structural steel and web trusses. But for some peculiar reason few have made use of off-the-shelf building systems, preferring instead to custom engineer and hand-fabricate structures even if they are otherwise similar to the off-the-shelf hardware and despite the great increase in cost this custom work incurs.
For a long time I have been looking for prefab building systems of lighter/smaller scale that can realize a practical pavilion home with the simplicity of bolt-together construction. Recently I observed that there was a strong similarity between one very common kind of prefab structure and many of the architect-designed structures; prefab metal carports. Designed as a quickly built and maintenance free shelter for automobiles, RVs, and boats and very common in the milder climate regions of the US, these simple structures are often used for other purposes such as workshops, outdoor lounges, and more. And being commonly made of aluminum and steel, they are basically non-toxic. It occurred to me that if one took one of these carports and added a window-wall of storefront glazing, some added flashing, and a suspended ceiling supporting more insulation one would basically have a miniature version of a typical Modernist pavilion home. This led me to an interesting idea.
Suppose that instead of a home being composed of a single building it was composed of a compound of small buildings, each one serving the functions of one or two rooms and linked to the others by a covered walkway. This isn't exactly a new idea. The traditional Spanish/Mexican hacienda is sometimes fashioned as a walled compound of largely independent buildings and un-walled compound homes can be found among traditional architecture in Asia and the Pacific -wherever a mild climate enables convenient movement between the small independent shelters. So I thought, why not something like this using mini-pavilions made from carports? I envision such a home being composed of 4-6 carports, each 20-24' square and featuring a 16-18' square enclosure consisting of three glazed walls with sliding doors and one whole-wall cabinet which contains the functional elements and utilities for each unit. The basic compound would consist of four mini-pavilions; bedroom, bathroom/laundry, lounge/office, and kitchen. A fifth carport would serve as a carport, featuring a cabinet wall as an outdoor storage unit. A sixth unit could be added as a dedicated office or workshop.
In studying this concept I have so far guesstimated that each mini-pavilion could cost between $4000-$5000 to build and outfit, putting the basic completed home compound at around $20k, plus the cost of land and any necessary improvements/utilities it requires. Not the cheapest approach but still economical and convenient in its modularity, each unit being saved for and stockpiled individually. And the individual mini-pavilions could be readily constructed by a lone individual with little difficulty. But there are some limitations. Energy use would tend to be high because the small structures would have very limited insulation. This is definitely an approach limited to the more optimal climate locations, like that in Hawaii or the more southern parts of Arizona and New Mexico. And perhaps the biggest limitation is its dependence on a site-built concrete slab foundation. This is something I could not make myself in my current condition, even if the rest of the structure should be something I could handle.
This idea may seem rather peculiar to most people but I was surprised to discover that I'm not the first person to have thought of it. It seems that just this year architect Pierre Koenig devised a virtually identical concept with mini-pavilions of the same size, though of course based on custom made pavilion structures rather than off-the-shelf carports. Images of this design can be seen Here. It does not appear that actual construction of this home has been realized and the layouts appear to be a preliminary design. But if one of the most experienced Modernist designers in the US finds such a concept promising, it clearly has potential. But without a solution to the labor problem of the foundation slab it is probably beyond my means.
Thinking on this problem, I wondered if there was a way to fashion a mini-pavilion that needed less on-site fabrication and eliminated the need for the foundation slab. This would be easy to do by using a raised floor deck system, the structures posts resting on relatively easy to install pre-cast pin-pier foundation units or screw-pilings. This is quite feasible but the only off-the-shelf product that can readily make such a structure is modular theatrical trusses. These are much more expensive and have no ready-made roofing or flooring system, though they can readily accommodate any type of roofing or flooring one can retrofit to them. I have long considered this an attractive structural system for larger pavilions. My article on Urban Nomad technology discusses this. But, again, at the larger size it starts to become too difficult for me to handle alone. Much custom fabrication would be needed to make the components for floor and roof and my lack of practical storage and work space in my current location is a critical obstacle.
A friend recently directed me to a site for a company called Lofty Shelters selling a clever hard shell pop-up tent that mounts on top of car and SUV roofs. It occurred to me that a similar structure using an insulated aluminum shell and made to the scale of a carport would offer a novel deployable housing system. Such a mini-pavilion unit would consist of a pair of large rounded edge square shells forming a hard transit case which is cranked open using a pair of scissor lifts and then fixed open by inserting four aluminum posts into sockets. The bottom shell would contain rigid flooring on top of a system of storage compartments in which deployable furnishings could be stowed. It would also features a foundation system in the form of four recessed corner posts with screw anchors. These would be ratcheted into the ground and screw adjusted to level the floor shell. The roof shell would contain more storage compartments above suspended ceiling panels and host more deployable furnishings, lighting, and perhaps a pop-up or built-in solar panel. Various appliances could be built into the storage compartments, such as deployable showers and toilets, air conditioners and heaters, and so on. Once fully opened, rigid window, wall, and door panels or a fabric wall system stored in the center of the shells would be fit between the shell edges to complete the enclosure. In the closed position, pin lock sockets in the shells would allow the units to be locked together into stacks for transport or for the attachment of wheels to allow groups of the units to be hauled over rough terrain or function as a complete road-worthy trailer.
Such a structure offers many advantages in that they could be completely pre-fabricated and deployed in minutes. Many sizes would be possible, allowing them to serve as more rugged and comfortable alternatives to tents for extended stays in remote areas. Could be a promising portable housing product. But, alas, this would be much harder for me to make by myself. This structure is clearly something that needs precision manufacture in a sheltered workshop environment -just like camping trailers. And in general it could never compare in economy to the simple carport. It looks like there is no practical way to make that simpler, even if it's still not easy enough for me to build alone.
Moving on to another housing concept, I have recently had a productive conversation with geologist Bruce Black, creator of Kokopelli's Cave Bed & Breakfast, a unique vacation home excavated from the face of a sandstone cliff in New Mexico. Mr. Black and I discussed the feasibility of building non-toxic homes in the same manner as homes built in the famous Australian opal mining town of Coober Pedy; by excavating them out of the solid rock. This is a concept I intend to discuss in detail in my next Gallery article. This idea has much going for it. Being able to exploit natural material on a piece of land for building a home is a good way to reduce cost. Using the landscape itself AS structure is cheaper still, assuming one can perform the excavation with minimum labor. Natural rock is completely non-toxic -as long as it's free of radon- and needs little or no finishing thus greatly reducing finishing costs. And the extremely great thermal stability of an underground dwelling means the nearly complete elimination of heating and cooling overhead in all but the most extreme climates.
Excavated dwellings are common in many parts of the word, including the Middle East, Africa, Spain, Turkey, and Greece. And as Mr. Black and the people in Coober Pedy have well demonstrated, they are comfortable, safe, and quite modern. But here in the US we are at a disadvantage for this kind of construction due to our relatively backward excavation technology. In Australia these homes are commonly made using a small version of a machine known as a roadheader -a common excavation machine in virtually every country except the US. Invented in the UK in the 1950s or 60s the roadheader is similar to continuous mining machines sometimes referred to as 'rippers' that are often used in coal seam mining. However, it is highly articulated using a pneumatically driven arm that allows it the reach to cut and dig rock in a large overhead area with the precision to carve very precise and complex forms. With its single or dual cylindrical cutting heads and sometimes laser guidance systems it can tunnel through most kinds of rock at a pace of about twenty feet per hour with only a single operator. In Australia, a couple of workers using a small version of one of these machines can excavate the structure of a complete 4000sf home in a single day and can finish it in a couple weeks. But as commonly used as these are throughout the world, few people in America have even heard of them. They seem to have been only recently introduced here, perhaps by the Big Dig project in Boston which was in part managed by a UK engineering team. The only routine use of these here seems to be by a couple of small businesses in California which use them exclusively for the construction of wine vaults for the Napa Valley wineries. Kokopelli's Cave was constructed by a combination of high precision blasting by a highly skilled explosives expert and a lot simple but rigorous hand labor. That's not likely to be a practical approach for the average person, let alone the likes of me.
Mr. Black has confirmed my suspicion that many places in the US Southwest are suitable for this kind of construction. In fact, the same areas I have been looking at for benefit of clean environment are also areas known for having the kind of calcite bonded sandstone this would require. There is also potential for this in Hawaii with its basalt rock, which offers the possibilities of some pre-existing natural lava tubes being ready to convert into homes. But finding spots with the correct geology -even where it's relatively common- would be a difficult task requiring some geology skill, a lot of field scouting, and a two-week test for radon at each prospective site. And the one thing I can count on is that the real estate agents will be of absolutely no help because they seem to be completely clueless about the physical composition of the properties they sell and put no effort into selling properties that aren't of high market value. Without readily available roadheader services in this country, it may be prohibitively expensive to build these homes relying on hand labor. But the machinery continues to shrink in scale and is, at last, beginning to appear in the US. Already one Italian company is selling roadheader cutting head attachments for small remote controlled excavators that could reduce this to a DIY scale. A possibility for the near future, if not the present.
Despite these problems, there is much potential in this concept. Bruce Black has proven it can be done even here and if I could find the right kind of help I could make this work. I'm particularly keen on its potential to exploit land of virtually no value to anyone else and to serve as the basis of novel eco-communities. More on this in my upcoming article.
