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C H A P T E R 4

General Issues in House Design

ONE OF THE MISTAKES that home designers — yes, even green homedesigners — make is failing to step back and look at the big pic-ture. Instead, they quickly get into specifics about materials,

construction details, and which appliances to buy. A better idea is tobegin your design process by considering a number of broad, overarch-ing issues. Whether you have hired a designer or are designing yourhome yourself, begin with the big issues, then zero in on the details.This chapter examines a few of these general issues, focusing on thosethat can help to make your home environmentally friendly.

IS A STAND-ALONE, SINGLE-FAMILY HOUSE WHAT YOU REALLY WANT?Since the 1940s, the American dream has been the single-family home.Billions of dollars in advertising, countless television shows, and a widerange of government policies have fueled our desire for that brand-spanking-new, single-family suburban home. For many, this image isrounded out by a shiny SUV parked in the driveway out front, a Sundayafternoon on the riding lawnmower, and a backyard deck looking outon their own “little piece of paradise.” Indeed, there is much to be saidfor owning a single-family home on its own lot. You have privacy. Youand your family make the decisions about how your house looks, how

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it’s landscaped, and the protection provided by your little oasis. You’rein charge.

But let’s take a look at some of the alternatives. As was noted in thelast chapter, green building is partly about building strong, vibrantcommunities. We are seeing more and more housing projects today inwhich the goal is not the single-family, stand-alone home located as faraway as possible from neighboring homes. We’re rediscovering thatcloser association with neighbors can be a good thing. We’re hearingabout cohousing and other developments where homes, or multi-fam-ily housing units, are clustered together on just a small portion of thesite, and most of the land is kept as open, undisturbed land.

Clustering buildings is environmentally beneficial for many rea-sons. More land can be kept open and available for natural vegetationand wildlife, the area devoted to driveways can be reduced, less distur-bance is required for buried utilities (sewer pipes, underground cables,etc.), and direct site impacts during construction can be reducedbecause a single staging area can serve a number of houses. With morepeople living closer together, public transit and shared transit are morefeasible. As you begin to think about your dream home, at least givesome thought to whether you really want a house all by itself, or

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FIGURE 4.1—The American image of an ideal suburban home is quite different than the

ideal green home.

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whether a house that creates or contributes to a sense of communitymight be part of your vision.

HOW BIG A HOUSE DO YOU NEED? The bigger the better, right? Isn’t that a part of the American dream?The average US home has more than doubled in size since 1950, grow-ing from about 1,000 square feet to 2,340 square feet in 2004. This hashappened even as the average family size has shrunk by one-fourth,from about 3.4 in 1950 to 2.6 in 2004. Today’s homes provide, on aver-age, three times as much square footage per family member (290 in1950, 900 in 2004). In fact, some of the largest homes being built todayare for empty nesters, couples whose children have left the home andwho are at the top of their money-earning potential.

What’s wrong with this picture? Plenty. The bigger a house, the big-ger its environmental impacts. Almost all building materials, even thosewe call green, have environmental costs associated with manufacture andshipping. And energy consumption is, to a significant extent, propor-tional to house size. So building smaller is better.

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FIGURE 4.2—By clustering houses, driveways can be shared, excavation costs for utilities

can be reduced, and open space can be protected.

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Early in the design process, carefully consider how big a house youneed. Try to design the house to use space efficiently. This may meaninvesting more money in design, since it’s a challenge to create small-er spaces that work well. Chances are, however, that any extrainvestment you make in design to optimize space in your house willmore than pay for itself, since a smaller, more compact house usuallycosts less to build and operate. Downsizing the house allows you toincorporate higher-quality products, additional amenities, and a high-er level of craftsmanship. Wouldn’t you rather have hardwood flooringwith natural finish instead of plywood subflooring and petroleum-basedwall-to-wall carpeting, or ceramic tile flooring in the bathroom insteadof sheet vinyl?

Some people decide to build a large house to provide for futureexpansion: in-laws moving in, for example, or a home office. While itcertainly makes sense to design for planned family expansion (a recent-ly married couple planning for children, say), when it comes tounplanned but possible down-the-road space needs, it usually makesmore sense to keep the house smaller — sized to your current needs— but design it to facilitate easy expansion.

DESIGN FOR DURABILITYNo matter what type of house you build, there will be substantial envi-ronmental impacts associated with its construction — from theembodied energy in the materials, to the solid waste generated on theconstruction site. The longer your house lasts, the longer the period oftime over which those impacts will be amortized, or spread out.

How do you design a house to be durable? First and foremost, thehouse should hold up well to the elements. This means choosing designsand construction details that are resistant to rainfall, humidity, heavysnowfall, flooding, intense sunshine, or other conditions that may beexperienced in your climate. In climates with more than 20 inches ofrainfall annually, it means designing with special attention to watermanagement — for example, sizeable roof overhangs; ground slopingaway from the house; and capillary breaks on the foundation footingsand exterior foundation walls, and beneath floor slabs. It means choos-ing materials that will hold up for a long time, sometimes even if thosematerials aren’t what would be considered the greenest (see Chapter 8).

Another requisite for a durable house is a durable design — theidea of timeless architecture. Try to create a house whose style will

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hold up well over the decades, or even centuries. Avoid trendy stylesthat are likely to lose popularity when the next fad comes along. Someof the trendy designs from the 1960s, for example, did poorly on sever-al counts when it came to durability. You won’t find many 30-year-oldgeodesic domes or yurts; most of those that didn’t rot out due to poordetailing have been torn down to make way for more traditional —durable — designs.

DESIGN FOR ACCESSIBILITY AND ADAPTABILITYLike it or not, most of us are getting older. In designing houses for thelong term, consider providing handicapped accessibility. Creatingentries, kitchens, bathrooms, and other spaces that can be used bywheelchair-bound individuals is referred to as universal design. If thehome you’re planning is likely to be the one you retire in, universaldesign is a high priority.

Needs change in other ways, too. Families grow larger, or the kidsmay grow up and leave the nest. You might start a home business thatrequires significant space. Houses that are designed to be adaptable tothe evolving needs of their occupants are likely to be around longer.

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FIGURE 4.3—Accessible design calls for wider doors, a way to get into the house without

stairs, key services on the first floor, and sinks that can be used by someone in a wheelchair.

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If interior spaces can be reconfigured easily with little actual con-struction, you’ll save money, and environmental burdens will be lower.Perhaps a less-used part of the house can be closed off and require lessheating and air conditioning. Some houses are being built today withmoveable partitions or room dividers, so that some reconfiguring ofspaces can be done with almost no effort. Providing a moveable parti-tion between a small dining room and a family room, for example,might allow the space to be opened up on those rare occasions whenlarge family gatherings or neighborhood get-togethers are held.

If an addition is likely down the road, pay special attention to thelayout of the kitchen and other key rooms. Some starter homes aredesigned so that they can be added onto very easily with only minimaldisruption to the house layout.

To reduce the cost and impacts of future additions or modifications,have your builder keep careful photographic records as constructionproceeds. If your builder doesn’t want to do this, bring a camera your-self during construction. Take photos, for example, of open wall cavitiesafter plumbing and wiring have been run, but before drywall has beeninstalled. Key all of the photos to specific locations on the house plansso that you will know exactly what you’re looking at. Keep the photos,photo key, and house plans together in a binder. Down the road, whenyou need to cut an opening through a wall or modify the plumbing fora new bathroom, you can refer to these photos and figure out exactlywhere you need to open up the wall with minimal disturbance. If a leakdevelops in a wall, such photos can be invaluable in finding and repair-ing it.

HOUSE CONFIGURATIONWhat should the basic shape of your house be? Should it be tall andboxy? Low and spread out? Long and narrow, or roughly square? Theseare fundamental questions that will have very significant ramificationsas to how your house is designed, what resources go into building it,how well it fits into its site, whether passive solar heating can play animportant role in heating it, and how easy it will be to keep cool.Thinking about the house configuration early in the design processmakes a lot of sense.

As the examples in Figure 4.4 demonstrate, a fairly tall, boxy househas less surface area for a given volume of space and thus won’t loseheat as quickly in cold weather — since there is less wall area to lose

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that heat through. A tall, boxy house also has less roof area to absorbsunlight, leading to savings in air conditioning bills. The boxy housewill also use less material in its construction.

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FIGURE 4.4— A tall, boxy house has less surface area relative to the square footage of floor,

so it will require less heating and air conditioning.

FIGURE 4.5— To optimize passive solar heating, the longer axis of the house should be ori-

ented east-west, providing more area for south-facing windows.

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On the other hand, the low house with more complex geometrymay be better suited to passive solar heating and natural daylighting,and it may be a more interesting house visually. It can also lend itselfbetter to outdoor living space (patios, decks, porches), thus providinginexpensive additional living area, especially in temperate climateswhere such spaces can be enjoyed over a long season. In the AmericanGreat Plains, a low house also has the advantage of being more protect-ed from heavy winds and tornadoes.

From a solar heating standpoint, a long, narrow house, with thelong dimension running east-west, usually makes the most sense. Thisway, there is more room to put windows on the south side of the house,to help heat it during the winter months. And because east and westwindows transmit significantly more solar gain (net heat from sunlight)during the summer months than south-facing windows, they con-tribute more to overheating. Thus, having less east- and west-facingwall area can help to control air conditioning costs. (See Chapters 6 and7 for more on energy design.)

WHAT ABOUT AN ATTACHED GARAGE? If you plan to build a garage, should it be an integral part of the house, as is the case with most suburban houses? Should it be attachedbut with just one common wall? Or should it be kept totally separate?

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FIGURE 4.6—From an indoor air quality standpoint, a garage should be separate from the

house; if that’s not possible, the common walls must be extremely well-sealed.

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This is one of the many areas where green building requires a care-ful trade-off between conflicting issues. The integral garage is the mostresource-efficient choice, since it requires the least additional material tobuild, but it also results in the greatest risk to homeowners from an airquality standpoint. Automobile exhaust leaking into the house from anattached garage is one of the most significant indoor air quality prob-lems in many homes.

If the site allows it, a totally detached garage is usually the bestoption. In a climate with inclement weather, consider an open, coveredwalkway between the house and garage, but try to keep the garage sep-arate. If that just isn’t possible, try to have just a single common wallbetween the house and garage, and provide a very tight air seal in thiswall. Avoid designs in which the house surrounds the garage, as it willbe much harder to keep fumes out of the house. (See Chapter 9.)

OTHER DESIGN ISSUESSome general design issues that should be considered early in thedesign process are not covered in this book, for example, the style ofhouse. Many of these issues relate to personal tastes and the local realestate market. Your Green Home will not debate the relative merits ofa raised-ranch vs. a Prairie style vs. a New England saltbox. That’s upto you and your designer.

Other broad design issues will be covered in other chapters of thisbook, particularly Chapters 5, 6, and 7, which address the structuralbuilding system, energy-efficient design, and renewable energy.

As you begin getting into the more detailed design strategies inthe following chapters, keep in mind the broad issues covered in thischapter. By controlling the overall house size, for example, you may beable to pay for higher-cost green features such as solar power. By think-ing about the relationship between the house and garage early on, youcan save a lot of time further along in the design process. Start withthe big-picture issues, then move to the specifics.

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