A catalog of non-toxic building systems.
Saturday, June 25, 2005Shipping Containers - Superbox
This housing concept has been the focus of much research by this author and by a large number of architects, designers, and DIY tinkerers world-wide. There is something strangely fascinating about the simple, cheap, ubiquitous, tough, and inherently modular shipping container. And it has been used extensively for housing worldwide, both makeshift and with the benefit of sophisticated architectural design. And there is seemingly great potential for non-toxic housing since these containers are made of metal and, in their insulated form, have stainless steel interior skins and aluminum plank flooring. But it seems that the adaptation of these to housing use varies greatly, ranging from the simple to the complex, the cheap to the impossibly exorbitant.
There are basically four kinds of shipping containers. The most common is the dry goods container which consists of a steel box frame enclosed by corrugated steel panel and with an open floor fitted with wood plank like the inside of many cargo trucks.
Next is the insulated container which has a steel box frame enclosed by flat welded sealed sandwich panel with aluminum, fiberglass, or steel on the outside, stainless steel on the inside, insulating foam in the middle, and a floor of extruded aluminum plank. These containers also often feature a recessed bulkhead on one end designed to mount a refrigeration unit.
Next is the open frame container which consists of a standard container box frame without walls or roof and retrofit mounts for tanks, bins, and machinery. These are very diverse. They are used for large portable machines like generators, for fluids and bulk granular materials, tanks for live fish, and more.
Last is the flat bed container. Not really a container per-se, this is like the flat bed trailers or rail cars which carry goods too large to fit through end doorways and so are strapped down to a flat frame with two vertical end walls that fold down when not in use. Sometimes reinforcement bars lock into the upper corners of the end walls and often a tarp or light flat walls can be attached for protection, though there is no attempt to make them water-tight like the usual containers.
Containers come in two standard heights, 8' and 9' 'high cube', and two standard lengths, 20' and 40'. Enclosed 20' containers typically have one door in an end. 40' typically have two doors. However, variants of dual-door 20' and single-door 40' are not uncommon. In addition there is an infinite diversity of speciality containers fabricated on demand for special applications, though they rarely appear for sale used. These include such things as containers with side doors, containers of shorter and longer than standard lengths, half-height open-top containers used for bulk materials, interlocking short containers that lock together to form a larger standard containers, 'butter dish' containers that have an upper portion that seperates from a lower flat bed container, nesting containers that hold other cabinet-like containers inside them for fork-lift removal, and so on.
Containers first began being converted into housing to serve the needs of the oil industry which used the containers for prefabricated worker housing on oil rigs. The typical conversion approach used for this and many other similar applications has been to re-frame the interior of a standard dry shipping container with light gauge steel or wood framing in order to host conventional insulation, wiring, and wall board or pre-finished wall paneling as used in manufactured housing. Variations of the standard end doors with normal sized entry doors are often used and in order to frame windows, side doors, and roof-top ventilators or skylights despite the corrugations of the metal plate a wide flat metal plate is wleded into the opening. At sea, the normal 'foundation' used is 'king pin' mounts which are welded onto a ship or rig deck to lock the containers down at the corners.
More sophisticated adaptations began to appear when industrial users started looking to containers as transportable storage, labs, telecom centers, and offices. The 8' width of a container is very confining. Two 20' containers joined side-by-side to form a 16'x20' unit is a much more convenient basic room size. So various schemes were devised to join containers together, permanently or temporarily, so the intervening side walls could be removed to make larger rooms. The three most common approaches for this seem to be the use of a bolt-together raised seam (akin the the way raised seam metal roof panels work), permanent welded joint plates, and secondary roof coverings where either a membrane is placed over the containers to cover the seams between them or a completely separate metal roof is placed on top of them. These combinations inspired many companies -though for some unknown reason none in the US- to start making joinable container module buildings for a variety of applications. The Erge Corporation of Germany is one of the better known makers of these kinds of container buildings systems.
On land containers are often used with no more foundation than a flat spot of ground or a bed of gravel but more permanent installations use concrete corner pads, concrete piers, reinforced concrete beams, or a shallow perimeter foundation akin to that of a conventional house. Sometimes even slabs are used, though this can be redundant unless one wishes to cast a concrete floor within the open bottoms of the dry containers. Heavy steel king pins or bolts are formed in place in these foundations to lock the containers down at the corners, though sometimes this is omitted if the foundation pieces are wide enough.
Inspired by the poor of the Third World who frequently modify discarded containers into make-shift housing, by their inherent modularity, and by the glut of containers in countries with high import volumes, many architects have experimented with containers for modular housing concepts. These range from fairly simple but clever shelters that revel in their small size and extremely space efficient interior designs to very elaborate structures that join numerous containers in odd ways or integrate them with mechanical contraptions resulting in very expensive structures. One of the best -in this author's opinion- of the current architect-designed container homes is a prefab home product called Quik House designed by Adam Kalkin of NJ. This is a fairly simple container combination based on 40' modules but produces a spacious home and is particularly interesting because the designer claims to be able to optionally provide these with an entirely non-toxic composition. However, this comes with a minimum $160,000 price tag. Most people tend to think of the container house as economical shelter but when architects get involved this is rarely the case, though the Quick House is quite modestly priced compared the the majority. A cheaper but also much smaller supposedly non-toxic container shelter called the Chuckhouseis offered by the Global Portable Buildings company. Their literature suggests awareness of the need for a non-toxic interior but some of their choices of interior materials are questionable. This author has never been able to confirm their claim or get materials details out of them.
Having done extensive study of the many ways containers have been adapted to housing, this author has found that the biggest problem in using containers for housing is the cost and difficulty of getting the metalworking services needed in the US. In the Third World its easy enough to find people to hack containers into any desired form for next to nothing and in those countries one sees containers, and parts of containers, repurposed to an endless variety of uses. Here in the US, however, everything one might want to do with containers is a Big Deal because of the limited experience of metalworkers compared to their Third World counterparts and a fixation of companies on a specialist industrial market. Though there are some specialist companies here that do some sophisticated container modification work and routinely make container housing for the oil industry, the application of housing on land is always considered unusual -if not bizarre- here despite the ubiquity of container housing in most of the rest of the world. And these companies are used to dealing exclusively with corporations whose executives are notoriously dim-witted about value, want everything 'yesterday', and will casualy accept any price. And so exorbitant fees are demanded for the simplest container modifications.
Unless one can perform the modifications oneself or afford one of these ready-made products a container home may be impractical here. But whether hiring the work or performing it oneself, the key to practicality seems to be the use of the container with as few physical modifications as possible. This means trying to make use of the simple 8' wide unit as a single room with few changes and with the end doorways used for windows and portals rather than the sides as framing can be retrofit there rather than mounted in custom-cut openings. Containers with dual-doors are obviously better in this respect.
Using containers in this way, it is obviously easier to design homes using a compound approach, though this limits the home to mild climate areas unless some other kind of 'skybreak' shelter structure, like a tension roof system, is used to enclose the compound. A custom coupler made of structural steel profile or recycled container frames and used to connect the containers in a star pattern or a commercial solarium product used as a front corridor for a linear group of containers might also be cheaper than joining containers side-to-side while eliminating the climate issue with open-air compounds. But it would be difficult to make a perfect seal between these and the containers so there may always be an issue of weather and insect infiltration.
Some designs have made good use of plastic membranes to seal container combinations together. The same types of materials used for moisture barriers in compound roofing systems, these are finished in the same way and effectively create a second roof over the containers. But there is still the issue of the seams at the container end and bottom to deal with by other means.
The insulated containers are by far the easiest to modify and best suited to non-toxic housing because the sandwich panel material used in their walls easily accepts the use of clamp-fit windows and doors as used on boats and in recreational vehicles. The material is also suited to the use of rivkels -rivet screw sockets- which allow for the screw mounting of paneling and fittings while retaining demountability. Of course, the stainless steel interior is ideal for the non-toxic shelter and allows covering and fixtures to be attached by magnets as well. But, unless bought new and unpainted, one must still strip and replace all exterior paints with non-toxic alternatives -a job most people who need non-toxic housing would not be able to do themselves.
While there remains great potential in the container housing concept, the labor/cost problems of their use in the US makes them less cost-effective than other types of structure unless one has the means to do all the adaptation work through sweat equity. Since that work can involve paint stripping and welding, it probably precludes the option of sweat equity for the MCS patient while the high cost of hired labor or ready made units may preclude the use of containers altogether.
An extensive listing of container housing projects can be seen at the Container Bay section of the Fab Prefab web site.
Steel Prefab - The Industrial Shelter
Another type of construction popular with Modernist designers, steel prefab structures -though almost never designed for housing originally- have frequently been adapted into a vast assortment of novel housing.
The most well known of these is the steel arch which originally appeared for agricultural uses and for aircraft hangars, was turned into dormatory style housing on innumerable military bases and industrial facilities, and then started being qidely sold for garage and similar out-building structures for the general consumer. Steel arches are very simply constructed, consisting of a series of nesting corrugated galavanized steel panels that are bolted together and lifted atop a concrete slab or rail foundation. Steel arches present severe design restrictions due to their curved two-ended shape but compensate for that by offering large clear spans. They have been easily converted into attractive homes by the use of sprayed foam insulation and simple commercial glazing systems or conventional light framing to close the ends. Some can be earth bermed. Steel arch could offer some of the lowest cost and quickest built housing possible but in recent years this potential has been stymied by their manufacturers' peculiar methods of hard-sell marketing which have driven away most creative users of the products by making legitimate pricing and technical information impossible to obtain.
Because they are composed of galvanized steel, steel arches offer good potential for non-toxic housing and could be one of the cheapest types possible. Combined with isocyanaurate or Airkrete foam insulation, earth berming, commercial window-wall end enclosure, radiant heating in the concrete slab floor, and the use of simple open-plan designs they are practically ideal for this if one can get over their shape. But the marketing practices of their manufactures seems to preclude this. It is simply too much trouble to deal with these companies today and that is preventing the construction of a lot of novel homes.
homes from prefab steel barns - American Outback Buildings
Next most common among the steel prefabs is the great variety of frame and panel box buildings. These consist of simple large span steel frame structures using various forms of trusses, 'red iron' framing, structural steel profiles, and light gauge steel framing which are enclosed in modular metal wall and roof panel. Some have pitched roofing in shed or shallow gable forms, some nearly flat roofs. Most all of them use slab foundations. Originally designed for quick-built agricultural and industrial buildings, these have also found their uses for housing and a few manufacturers actually offer building packages designed for that purpose. Housing adaptation is straightforward, usually relying on the light re-framing of the interior in order to host conventional insulation and wall board products. Once finished in this way, interiors are indestinguishable from conventional homes. The many barn-like designs are especially well suited to housing. Though marketing from some manufacturers are as troublesome as that of the arch makers, sales people are typically much more knowledgeable about their products and less averse to the notion of housing uses and so these buildings have seen much more use in housing recently than arches have.
Adaptation of these for non-toxic housing is not difficult but a little more care is required than for typical housing adaptations. Not all the manufacturers use non-toxic primer paints or galvanized coatings on the metal work so one must first be sure that the basic structure is truly inert. Galavanized components are preferred, though the colored exterior coatings of roof and wall panels are usually baked-on coatings which are typically very inert. Interior finishing requires the use of alternative non-toxic wall board or paneling products, as does any interior partition framing. Some of these products offer insulation based on metalized polyethylene foam sheet which should be well tolerated by many MCS patients. Since the materials are impermeable, active ventilation is a necessity unless in mild climates and with structures using open plan design and large opening windows offering good cross ventilation. The modular windows typically offered with these building packages are often not adequate for some housing applications and often feature vinyl frames isntead of the more intert aluminum. Commercial windows products are usually easily adapted to these, given that the structural framing accommodates it. Often standardized garage door openings make for effective window-wall placements.
assorted steel park shelter forms - Poligon
The third kind of prefab steel structure suitable for housing adaptation is the pre-fab park shelters. These are simple open-side pavilion structures used in parks to shelter picnic tables or as gazebos and sometimes are host to various concession stands and service kiosks. They are typically based on a structural steel profile frame mounted on piers and supporting a metal panel or wood roof. Though these have rarely been used for this to date, their potential is great. They offer very attractive designs with large spans which can be simply converted into pavilion style housing simply by building them atop a slab foundation and enclosing them in commercial window-wall glasing and/or in-fill wall construction of most any material. They are suited to uniform free-standing buildings, sprawling structures, and 'compound' designs where individual rooms are contained in individual smaller buildings with open-air or enclosed pathways between them. hey are not well suited to multi-storey structures except where a free-standing mezzanine structure is used to host upper floors.
For non-toxic housing, adaptation is no different. The only caveat is that one must be sure the shelter structure is finished with non-toxic coatings. A few companies offer galvanized steel or baked enamel frames but most are simply painted. Since these structures favor pavilion designs, there is little finishing required. If a window wall enclosure is used, one need only deal with the floor and drop-ceiling coverings and complete the finishing with free-standing furnishings. This is one of the great virtues of the pavilion architecture approach when it comes to non-toxic housing, though not everyone is comfortable with a very-open-plan design. It is certainly not suited to closely grouped housing, but most MCS patients will seek edge-of-wilderness locations anyway where these are aesthetically ideal.
a modular mezzanine system
The fourth type of prefab steel structure suited to possible housing adaptation is the industrial mezzanine. Though rarely used in housing, industrial mezzanines are very similar to the park shelters in structure and can be used similarly for both single-storey pavilion style structures and multi-storey structures using commercial curtain wall systems as used in heavy steel frame structures. This includes non-toxic housing as well, though there is more ignorance about paints in this community of manufacturers and galvanized steel, though available, is much rarer. Some have great potential as modular building systems, featuring standardized bolt-together modular components which can be combined in endless variety, although limited to box shapes. The key difference with therse is that they have no roof. They are designed for use inside other large clear span buildings. But they can readily accommodate either compound flat roofing or metal panel roofing. Why these have so rarely been used for housing is a mystery considering their great potential. It may have to do with the lack of cooperation from manufacturers who simply have no concept of these being used for anything other than the one application they were originally intended for.
Heavy Steel Framing - The Residential Skyscraper
Heavy steel framing -or 'red iron' as it is sometimes called- has only rarely been employed in residential construction, with the exception of its use in the commercial-style construction used to build very large apartment complexes. But it has often been a favorite of Modernist designers who have sometimes employed such sophisticated custom craftsmanship in the fabrication of frames for visual effect that it has rivaled that of traditional wood post & beam construction -and often radically increased cost as well.
The use of heavy steel framing in homes is done with essentialy the same construction techniques employed in commercial construction, just with different designs that produce more comfortable habitats. The structures are built in essentially the same way as a skyscraper, using a post & beam or 'ramen frame' arrangement with posts set on foundation piers -sometimes integrated into a slab or basement wall systems- that relies on the massive and high strength nature of the frame components to allow for large spans and tall structures. Concrete sub-flooring -and sometimes sub-roofing- is the norm using corrugated steel plate decking to support the concrete pours and with the option to integrate radiant heating and electrical/plumbing conduits. A curtain wall system and often large expanses of glass are then used for enclosure along with compound roofing or metal panel roofing. Interior partitions are typically framed in light lumber or light steel with conventional sheetrock paneling.
There is much potential in this building technology for non-toxic housing but it has almost never been explored. Structures can be built quickly, rely on open-plan designs thanks to large spans, and in Modernist designs often make extensive use of inert materialsd for finishing and enclosure such as glass, metal panel products, ceramic panels, tile, and stone. The chief caveat of using this material is that the otherwise ideally non-toxic steel can be made toxic if the primer coatings applied to it are composed of toxic paints. Some are, some aren't, and you will almost never find a supplier in the US who knows the difference. There are no boilerplate plans for homes based on this kind of construction and the huge heavy components typically require heavy machinery to handle. They are almost always archiect-designed and built using commercial rather than residential contractors. Thus the use of this approach may not be practical from a sweat-equity standpoint. But the potential is great, especially for homes based on this author's favorite type of pavilion architecture.