Home Spun- Water Harvesting Prefab Urban Housing
Home Spun is an urban housing project that proposes low maintenance, easily deployable dwellings that impose minimal stress on a city’s services infrastructure. It is composed of small (400sqft footprint), prefabricated two level houses that can be tightly clustered on existing building lots. Using a variety of technologies including lightweight tape winding fabrication, parameterized parts that can be mass customized and integrated water processing through living machines, the houses have a unique morphology capable of harvesting water from precipitation, using it to heat and cool themselves and providing for domestic consumption. We see this type of multi-dwelling housing as a responsible way to redevelop underutilized downtowns in the many shrinking cities of the Great Lakes region of North America. Due to the loss of manufacturing jobs, cities like Buffalo, New York; Cleveland, Ohio; Detroit, Michigan and Hamilton, Ontario have seen steady depopulation. This has caused urban fabric deterioration as dwellings fall to abandonment resulting in pockmarked blocks and underutilized lots. Home Spun urban housing can be instrumentalized to reinvigorate such city blocks by developing an alternative urban typology that is mutable to nonadjacent and ill configured city lots and does not add undue burden on existing services.
Great Lakes/Rust Belt Meso region: climate and economic influences
The houses are ideally suited for a climate zone where precipitation is consistant throughout the year. In addition, as urban densifiers they are suitable for cities that need to repopulate their downtowns without putting undue burden on existing infrastructure. The Great Lakes Region offers such an area where many cities are suffering from urban shrinkage due to population depletion. This has resulted in low density urbanism that inefficiently uses space. Taking two types of urban conditions as initial examples: a pockmarked urban block where houses have been abandoned or demolished and a deep block with a service alley running down its middle; small, easily deployable houses can begin to positively add utility to such underdeveloped and underutilized spaces. They can also catalyze an alternative urbanism of collective living resulting in micro neighborhoods and alternative block configurations.
Water is plentiful in the Great Lakes Basin with abundant ground water sources as well as accessible aquifers. Sandwiched between the Great Lakes and the Atlantic the eastern side of the Great Lakes basin has abundant precipitation year round. Normally a plus in these times of global water shortage, this abundance has created a crisis due to outdated drainage systems that cause combined sewage overflows (CSO) in most eastern rust belt cities. Although urban density has not necessarily increased in the region, manmade impervious surfaces have proliferated due to suburban expansion exacerbating the runoff problem. Meanwhile the growing numbers of empty lots scarring the urban fabric do little to increase on site storm water retention.
When the services infrastructure was planned in these cities in the early 20th century, the surrounding land retained the majority of precipitation on site. This is no longer the case due to the proliferation of suburbs with their impermeable surfaces and oversaturated water tables. The region receives 25 to 50 inches of precipitation a year. Ideally this water should be retained on site and percolated down to the groundwater finding its way to the aquifers. The EPA has mandated that communities reduce and ultimately eliminate CSO’s to comply with the clean water act. The response has been to spend millions on large scale temporary containment tanks that hold the water until it can be sent through the sewer system. Onsite retention is only developed through small scaled landscape interventions which may help regenerate the aquifer through infiltration. These roles are relegated to green infrastructures and tend to develop an either or relationship between the built and the green space and its capacity to retain water.
As cities in the rust belt pursue options to redevelop their downtowns to attract new businesses and young professionals, they will need to contend with the added burden this will place on the existing services infrastructure. To alleviate the increased load on the energy infrastructure, grid energy systems are being developed to work with individual housing units. However, water systems have not been reconsidered and remain fully dependent on the existing infrastructure for both supply and waste. A sustainable and economically viable way to address this problem would require less city sourced water to be routed to new housing as well as less storm and sewage water to enter the city sewage system. This would place the onus of water supply and waste on the new development’s architecture rather than the existing infrastructure. Housing would need to harvest and treat its water onsite.
Home Spun urban housing provides a sustainable solution to this problem. Using Buffalo, New York as a typical eastern Rust Belt city for the test site, we explored the viability of water harvesting from precipitation. Located on the north coast of Lake Erie, its precipitation levels are higher than average of the Great Lakes basin due in part to the lake effect snow which often raises precipitation levels to 50 inches per year. However, even in this water rich region, without the implementation of severe conservation measures an urban lot could not support its own water needs even if it collected and used all the precipitation that fell within its property lines. The houses while not completely off the grid would provide negligible increases to city’s water resources.
One of the consequences of urban depopulation has been the deterioration of the urban fabric. Large single family houses in which extended families and servants once lived have fallen to disuse, abandonment, arson and demolition. The resulting urban fabric is pockmarked with non adjacent empty lots upon which it is neither economically viable to build another single family house nor are there adequate resources to build conventional multi-dwelling apartments. Home Spun houses exhibit a unique morphology which allows them to pack together in ad hoc ways. This makes them ideally suited for difficult lots where flexibility of orientation is required. The housing’s site development strategy uses a voronoi packing algorithm to address site layout of adjacent and non adjacent lots. This allows a bottom up approach through which new circulation and micro neighborhoods can develop in the block.
In addition, due to the efficiencies of scale this model proposes it allows for an efficient reclamation of grey water. The same principle permits the application of solar energy for both thermal heat gain and electrical production to all the units regardless of their distribution to solar access. The units are not only integrated to their environment, but responsive to each other making it possible to create micro climates within the lot. These in-between spaces can provide useful habitats for fauna and flora through the winter month. In addition, air can be drawn through or blocked by these cavities simply through the interaction of the unit’s thermal zones.
Anatomy of the Home Spun House
The Cistern housing and flow through lots respond to the both cultural models of material use defined by Reyner Banham in Architecture of the Well-tempered Environment. In unison, they attempt to neither consume resources by turning them into energy, not use them to build a shelter bound to a permanent location. The lightweight skin allows it to function in both first by becoming the conduit for energy absorption through thermal heat gain. Secondly, its thermal, water, and energy systems can achieve some autonomy allowing it to be relocated. Banham went on to speak of an architecture defined by its systems rather than a dichotomy between structure and skin. In the Cistern House systems, structure, and skin are defined by the configuration of the fiber reinforced composite shell.
The Earthship house, developed by Michael Reynolds over thirty years ago, is an interesting model of sustainable living. In The Natural House, one of many guides on sustainable living, Daniel Chiaras contends that the Earthship is “a demonstration of the wisdom of fitting in … it reflects the knowledge that we humans are part of nature”. As in the majority of these texts, the “natural house” tends to be an isolated, off the grid, rural or suburban construction. It would be more productive to look for a means of fitting into existing urban infrastructures, rather than expanding outside them. However, there is much to learn from the Earthship. Like it, the Home Spun houses are defined by a living space, an environmental interface “corridor”i, massive cisterns and a relationship of these components to the sun.
The water collection for an average city lot, upon which 8 to 10 units can be deployed, is not sufficient for a conventional US consumer. In response, each house is functioned with collecting all precipitation, communally treats grey water for reuse, and using water conserving appliances. The two story house, occupied by two individuals, contains a portion of the communal grey water treatment facility and its own water storage and purification systems. It collects rain and snow from its roof, stores it in its structural columns, and treats it for all household needs. Both skin and structural columns are water cavities that serve both thermal heat gain and water use. A living machine located on first level processes grey water and the same cavities allow for water to be pumped back up for bathing and cooking. This provides a third of the occupant’s water supply.
The landscape which flows in and out of the ground floor of each unit regenerates the grey-water for the community of units, and recharges the water cycle allowing for both transpiration and percolation beyond the site boundary. This process provides the remaining two thirds of the needs of a house unit, allowing the lot to function off the water network after its initial charge. The community of houses will use the city water inlet for the lot for this initial input of water, and they will connect to its sewage outlet for the black-water removal. This process will maintain a balance on the site of water use and may even allow some of the water to flow into the aquifers.
Manufacturing: Filament Winding for Fiber reinforced Composite Shells
Filament or tape winding fabrication is used to create the strong but lightweight prefabricated housing components. These provide the advantage of easy deployment and low energy usage in transportation. However, a significant problem with lightweight construction is its low heat retention. The houses address this problem by using the water they harvest to create the necessary thermal mass. Water, in addition to being a usable amenity in the houses, also provides excellent insulation and a medium for heating and cooling.
Filament winding manufacturing technology has been traditionally used for the manufacturing of pipes and storage tanks. Fiber reinforced composite water tanks have been shown to be more sustainable than concrete tanks for long term water containment. They are both more stable and have less embodied energy in their life cycle. More recently tape winding thermoplastic manufacturing, which works on similar principals, has been used to build high performance parts for automobiles and airplanes, where formal adaptation is the goal. Both provide a lightweight high strength construction method that can be applied to the prefabricated housing.
The house’s form is generated with the manufacturing process in mind. A large variety of rotational forms can be derived from shifting center points of end curves and altering curvature along the extrusion. The houses can be customized within a fixed set of parameters that still follow the same manufacturing processes. This formal variety makes them more customizable to the contingencies of the siting and other environmental requirements.
The house’s structure is developed from composite plastic pipes woven from straight lengths and 90 degree elbows. This cage acts as the scaffold around which the thermoplastic tape is wound, fusing with the pipes to create a very strong but lightweight composite construction. This creates a complete level comprising floor, structural columns, and ceiling with a skin/structure similar to that of composite plastic airplane wings. Then using hand lay-up techniques on the opposite side of the same ribs, pockets are created that will conduit water for thermal heat gain in the cool seasons. The ribs are then extended to the outer surface, and the exterior skin is applied in the same manner to complete the storey. The roof is manufactured through the same method. The house also integrates its furnishings into the skin of the house. Vacuum formed plastic is used to make the cabinetry while kitchen counters and work surfaces are CNC milled.
The prefab composite plastic house parts are loaded on a flatbed truck and transported to the site. Using a small crane, they are installed onto pre-poured foundations. Level 2 is mechanically connected to level 1 and the entire house is initially filled with city sourced water to begin inhabitation. Each floor is delivered fully equipped and fitted for it’s on and off the grid utilities hookups. The only amenities required from the city are an electric connection and black water disposal.