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DESIGNING AND DEMONSTRATING SUSTAINABLE MULTI-FAMILY ATTACHED HOUSING
Impact/Purpose:
This project aims to design and build sustainable, multi-family attached dwellings. The purpose, through design and construction of demonstration housing units, is to develop a cost-effective, environmentally-friendly housing that is both innovative and minimizing impact on human health and the environment. This project will evaluate the environmental, human health, and economic costs and benefits associated with several green building technologies including straw bale, insulated concrete forms, or a hybrid design of these two technologies versus conventional wood framing methods. The ultimate goal includes maximizing energy efficiencies in the structural design, materials, appliances, and landscape design; eliminating materials that generate hazardous by-products during manufacturing, use, and disposal; and responding to external environmental factors such as passive heating and cooling, daylighting, site orientation, and efficient storm water management. These strategies will all contribute to minimizing the environmental impacts associated with constructing multi-family dwellings – a challenge that has not been widely studied from this prespective.
Description:
The primary outcome of this research is a housing product that addresses evolving human needs, economic viability, and issues of environmental impact. The product is referred to as the sma|rt_1 home. Sma|rt is an acronym for sustainable, modular, and adaptable residential technology. A pilot project including four duplex versions of the sma|rt_1 home will be built by Habitat for Humanity-Spokane with assistance from students from Washington State University Spokane beginning in July 2007. Habitat for Humanity-Spokane reserves the right to alter any design features of the sma|rt_1 home during implementation. The site for these demonstration units is located within the city limits of Spokane, WA.
People: evolving human needs
Through unique design features, the sma|rt_1 home can adapt to meet the current and evolving needs of the homeowner. Building upon the concept of the grow home (Friedman, 2001), owner improvements can be made to the sma|rt_1 home in response to changes in lifestyle. Unfinished attic space and an integrated covered porch provide areas for future expansion. This allows for a three bedroom unit to be improved over time to accommodate four, five, or six bedrooms without altering the structural form of the building. This translates into a 55% net square footage increase from 1,120 to 1,740. Homeowners with limited building skills can perform these modifications with little or no professional assistance. The owners of the pilot project units will have the requisite skills for these types of modifications. All Habitat for Humanity homeowners are required to contribute 500 hours of sweat equity in the construction of their home. This helps them develop basic skills in carpentry and home construction.
The design of the sma|rt_1 home includes front and rear covered porch areas that are integral to the form of the building. These are intended to serve dual functions as homeowner amenities and solar shading devices. Alternative kitchen and dining room arrangements are identified to meet specific cultural or functional homeowner needs. Provisions for interior material and finish options are also provided. Design plans are developed for future homeowner initiated improvements including bedroom and bathroom expansion, additional built-in cabinetry, upgrades of interior trim, exterior benches and planting areas, and energy efficient appliance upgrades. A homeowner’s manual has been developed for the sma|rt_1 home including in-depth instructions and drawings to guide these home improvement projects. This empowers the homeowner to improve their property in an affordable manner while increasing resale value and aiding in economic security and independence.
Prosperity: economic viability
The sma|rt_1 home targets the first time low-income homeowner. Affordability is achieved through lower initial construction costs and reduced life cycle costs due to simple, responsive, energy efficient design. The sma|rt_1 home realizes lower initial construction costs as a result of efficient use of building materials and minimization of waste. The design is based on a two foot module with an overall dimension of 14’ x 52’ for a single unit (duplex structures are 28’ in width). A major benefit of this approach is that many conventional building materials are sized as a function of the 2’ module. This saves in material waste and aides in rapid construction.
Over the life of a structure, energy use consistently represents one of the highest expenses, and given future predictions of mounting demand and escalating costs, this will likely increase in significance. Reduction of energy use is achieved in the sma|rt_1 home through a combination of environmentally responsive design strategies including passive solar design, day-lighting considerations, passive ventilation, and highly insulated wall and roof assemblies. By decreasing energy needs for heating and lighting, the sma|rt_1 home reduces the overall, long-term expenses associated with the home. These efficiencies and the resulting cost savings help to make the economic benefits of homeownership possible to lower income levels.
Planet: issues of environmental impact
The sma|rt_1 home combines energy efficient and environmentally-responsive building design with low impact site considerations and sustainable construction materials and methods. Insulated concrete form construction for walls combined with a structural insulated panel roofing system are identified as the most energy efficient, cost-effective, low skill labor friendly, and environmentally benign method for the exterior construction. Roof gutters will be installed that feed into retentions cisterns to provide water for landscape maintenance. Generous south facing windows are incorporated in the design to provide natural light and passive heating. The design specifies low toxicity construction materials and finishes to support human health and comfort through improved indoor air quality. The sma|rt_1 home integrates energy efficient equipment, and low flow shower heads, toilets and faucets. Energy star appliances have been identified for the refrigerator, dishwasher, and clothes washer. Surface mount and recessed can lighting is specified using compact fluorescent lamps. A high efficiency electric-on-demand water heater serves the radiant heating and domestic hot water needs. To maximize the life of the on-demand heater, a central water softener is also specified. Because it is a duplex, the sma|rt_1 home will also enable higher housing density with reduced costs and environmental impacts as compared to single-family detached homes.