Page 34 RAIN Summer 1986 The addition of a solar greenhouse provides multiple benefits such as lower heating costs, a place for plants, improved thermal comfort. (FROM: Sustainable Communities) area off the street, with primary private and shared space along common areas in back. These design principles can be applied to suburban redesign with relative ease (see title-page illustration). The use of narrower and fewer through streets also encourages the use of walking and bicycling within the neighborhood, particularly since, with many streets closed, foot and bicyde paths would offer the most direct path between points. Another implication of narrower streets is the use of low-speed mini-vehicles for many types of local trips that are now performed by fall-sized automobiles. Density and Diversity Within the Block As we have seen, the idea of the suburb.was to provide separate homes for nuclear families, once the doininant social form in the country. However, social structure has ~een changing rapidly, with some regional variation. While the family consisting of man and woman and one or more chil: dren is with us to stay, the number of households·composed · of unattached individuals of one or both sexes has increased dramatically, as has,the number of single-parent households. Combined with a vast increase in the number of women in the work force, a lower birth rate, and housing costs that have risen far more rapidly than real income, this is having dramatic effects on housing patterns in the suburbs and elsewhere. People can purchase less space today for the same proportion of their income. Yet, much single-family housing is underused, when it is still occupied by parents whose children have left. Single parents band together to share child-rearing, and singles find that they must share housing and use facilities cooperatively. All of these trends point to opportunities to redesign the suburb-an block pattern toward greater density of use and ·more adaptable housing forms. In many parts of the country, housing costs, economic pressures, and changing demography are already producing changes, though perhaps they are not well documented, because they largely exist within what economist Scott Bums has called the 'Houshold Economy.' Owners eager for some added income, or to accomodate the housing needs of a child or relative, tum basements, at1 •• tics, and garages into 'in-law' units, which are generally not permitted in 'single-family' neighborhoods. People increasingly run small businesses out of their home, again violating single-use zoning·didums that were intended to keep ·'harmful' or conflicting uses out of exclusively residential neighborhoods. What we advocate is·to indeed encourage these kinds of densification and diversification of the suburban neigh- · borhood. From the point of resource use and sociability, the suburban density of six to eight houses to the acre, or about fifteen to twenty people per acre, means a high per-capita cost of building and maintaining services such as roads, utilities, and any form of transportation. From the point of view of ·sociability', it is a density that is too low to support comer stores, cafes, and all the kinds of places we associate with conviviality. In the suburb, the locus for the neighborhood becomes the backyard potluck and the Saturday TV football game. In the Su~yvale case study, we proposed that in exchange for closing streets and clustering parking (which might mean in ~ome cases that people would Ii ave to walk several hundred feet to their houses)," zoning would pennit 'zero lot lirie' additions to dwellings and the addition of second units. Increasing density within the block pattern goes hand · in hand with remodeling to add space and improve energy use by reducing energy losses, as well as making direct use of· the sun for heating. At the residential scale, conserving energy is always more cost-effective than redesign to capture · additional sources of energy supply. So the cycle of remodeling and adding on to the suburban home will be combined with conservation measures such as insulating walls and ceil-. ings, replacing single glazing with double glazing, reducing infiltration by adding vestibules, and providing air-to air heat exchangers. Once these basic steps to increase comfort and reduce energy loss have been taken, the stage is set to further reduce the need for external energy by capturing the sun. The solar techniques that work best in remodeling or 'retrofitting' existing small buildings include the 'solar attic' and solar greenhouses. The solar attic approach works in houses that have pitched roofs. The rafters and ceiling are superinsulated and lined with black plastic. Double-glazing panels are installed in the southern slope, together with 'heat rods': plastic tubes filled with salts that have (20x) times the heatretention capacity of dense materials often used for heat storage such as concrete. The heat captured in the attic is then distributed through a conventional duct and fan system to · other parts of the house. The advantage of this system, besides its relatively low cost, is that it makes use of space that is already built and cannot be used for living. The solar greenhouse consists of a wood-framed, plastic enclosed addition-often only four feet to six feet wide, built off a smith side of the house. It acts as an extra wall, reducing heat loss and capturing heat when the sun is shining. This simple addition, which also serves as a place to grow salad vegetables year round, can be built for less than a thousand dollars. A more elaborate solarium room provides additional living space and thermal capacity in mass walls or floors which hold onto the sun's heat. In summary, ·a move toward 'living in place' brought about by a slower growing, more localized economy and persistently high fuel costs will have profound effects on the traditional form of the su~urban block. Cars will no longer be the exclusive means of transportation for all trips, and the
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