In many ways, choosing a site is the most important decision when constructing a green home. From a design perspective, a site limits the orientation of the home and determines the location of windows. From an environmental perspective, a site determines if a homeowner must own a car to travel to the grocery store, work, and school. Finally, from a community perspective, a site changes the feel of a neighborhood. Thoughtful site decisions are crucial to constructing a green home. This page outlines the principles and process for effective community and site planning for green residential design.

Types of Sites

Brownfield sites are previously developed areas that have some contamination present that needs to be cleaned up before the site can be used again. Not all brownfields are created equal; some need little or no clean-up, while others may need extensive work. Builders should consider the benefits (typically prime locations and government subsidies) and balance these against the clean-up costs and disadvantages of a site. Many organizations, like the U.S. Environmental Protection Agency (EPA), offer grants for contamination assessment, clean up, and site remediation job training. After Hurricane Katrina in 2005, environmental remediation of contaminated land became a common construction practice in New Orleans.

Greyfield sites are those that have been previously developed but are not contaminated. Typical examples are demolished schools, amusement parks, old malls, and, at the largest scale, airports (although these invariably contain pockets of brownfield sites). These sites offer the possibility of providing a carefully planned mixed-use development within or close to existing development, filling in a “missing tooth” in the urban fabric, and avoiding the development of outlying farmland. In large projects, there are often excellent opportunities for developing sizable wildlife core refuges and linking corridors.

Greyfield Case Study: The Stapleton Airport.

In 1988, the Stapleton Airport in Denver, Colorado, was decommissioned in response to growing complaints from the nearby community and the need to add an additional runway. The airport was replaced by the Denver International Airport about 20 miles away. The decommissioned land was then transformed into a redeveloped residential and retail center. The old airport now serves as the site of 12,000 homes, six schools, a light-rail station, offices, retail space and over 1,000 acres of park. The once greyfield is now one of the largest and most sustainable developments in Colorado.

Sustainable Site Development Layout

Scattered-Lot Infill Sites: One way to raise settlement density and avoid the development of open space or farmland is to “fill in” vacant lots. Infill sites are typically more expensive to develop than greyfield sites because they are scattered, access is sometimes constrained, and permits must be obtained one-by-one. The added costs are partly balanced by savings from using existing infrastructure and from local incentives (mentioned previously). Local small builders can typically build on scattered-lot infill sites more economically than larger companies, because they can shepherd permits through the official channels and pay attention to the complexities of building non-repetitive homes in tight quarters.

Open Space: Clustering homes enables parks and other open spaces to be preserved for recreational or environmental purposes. Developers have found that they can cluster well-designed homes into a more densely populated community and preserve open space at a greater profit than if they had developed the area in a more traditional manner. Most home buyers are attracted to, and some are willing to pay a premium for, homes that are adjacent to open spaces, recreational areas, or other amenities. Clustering can also foster an increased sense of community.

Paved: Generally, builders should try to reduce paved areas for streets, alleys, sidewalks, and parking lots. It is possible to reduce the paved area in a subdivision by as much as 50% (15% of the land being developed rather than the more typical 22-27%). Where paved areas are created, consider using pervious materials to reduce storm water runoff or using lighter colored paving materials to reduce the “heat island effect.” In addition, take advantage of recycled materials, such as less-expensive aggregates that reuse asphalt and concrete. Planting trees in the parking strips may help reduce the heat island effect.

During the development phase, consider narrower streets to reduce paving materials. However, the reduction in paved area can often only be achieved by adopting incentives that allow reduced road widths and parking requirements. A side benefit is that motorists slow down, allowing pedestrians and children to more safely use sidewalks, lawns, and, in smaller communities, even the street, as impromptu community gathering areas. As always, design decisions require integrated thinking. Consider this simple but interesting example. Most sidewalks are 48 to 54 inches wide, just wide enough to accommodate two people walking past one another. However, designing sidewalks to be up to 72 inches wide could help meet other goals, such as to accommodate people with disabilities or to encourage children to play on the sidewalk rather than in the street. In any case, consider placing a sidewalk on only one side of the street.

Designing the Site

No matter what the density of a development, the site a home occupies determines major aspects of the home’s design. For example, in a typical subdivision on relatively flat land, homes are almost always designed with most windows facing the street and the rear yard, with only secondary bedroom, bath, or kitchen windows facing the narrow side yards. Homes are typically designed in specific widths so they will fit on specific sizes of lot with the required setbacks. This section delves into the design aspects associated with different site characteristics.

High Density

As the density increases, the lot and street layouts determine the size and orientation of the homes more and more. The site planning (except for detailed landscape design) and the amount of solar access are determined entirely during the land development stage. In a typical site plan, the builder should take advantage of the solar opportunities made available during land development, compensating in the detailed design of the home for less than ideal circumstances.

What can a builder do when setting homes in a medium – to high – density subdivision if solar access and views have been ignored in laying out the lots and streets? Suppose, for example, that the street side of a relatively wide lot happens to be on the west. The simplest measure is to develop home plans with enough flexibility in the design so that some of the windows can be placed on the south side instead of the front or rear and so that living spaces and bedrooms, instead of closets and bathrooms, end up on the south. This may require flipping the plan right to left, or in a two-story home, flipping one story relative to the other (if that is possible). Home styles that feature informal, asymmetrical elements are easier to work with than classical “colonial” homes that emphasize symmetry at the expense of flexibility in plan layout and window placement.

Another approach that works on relatively wide lots is to orient the home sideways on a west- or east-facing lot so that its major facade faces south instead of west (toward the street). In most cases, turning the house requires some ingenious landscaping (fences, hedges, pergolas, etc.) to guide the visitor to the front door. What seems to be a problem can often turn into an opportunity for inventive design, and the end result may prove more interesting than a conventional, street-facing design.

Low Density

As density goes down and building sites become larger, there are more options for locating and designing a house to take full advantage of desirable sun, views, and breezes. Homes can more easily be protected from undesirable sun, views, wind, noise, rain, and snow. Along with freedom comes responsibility, and large sites raise new issues that must be considered during site planning. A large rural site, for example, is not likely to be served by urban utilities, and may need a septic system, a water well, and a long, paved entrance driveway. On the other hand, on a remote site, an array of solar cells may be selected as a source of electricity instead of a diesel generator, with the advantages of being quiet and not relying on any fossil fuel.

Of the wide variety and extent of issues that must be considered to build green on a generous site, some of the most important are the following:

  • How the sun moves across the sky at the latitude of the site
  • Shading by mountains, slopes, or large trees
  • Shading by regular morning or afternoon fog
  • Direction of prevailing snowfall and drifting (for example, entries facing northeast in New England can become completely plugged with snow, so New England Colonial farmhouses nearly always had the front door facing south or southeast)
  • Direction of cold winds in winter (so protected outdoor spaces can be located out of the wind)
  • Direction of cooling breezes in summer (so the home can be cooled by natural convection without mechanical air conditioning)
  • Surface water drainage
  • Underground water drainage and soil type
  • Existing wetlands
  • Attractive car access without excessive grades (especially in areas requiring salt or heating), without disrupting drainage on the site, and with areas to pile plowed snow without damaging native plants or trapping runoff water
  • Attractive car parking that does not dominate the site and create large paved areas
  • Location uphill from the septic field to avoid the need for pumping sewage
  • Orientation toward desirable views and away from undesirable present or future development on adjacent sites
  • Understanding of soil types and the type of plants best suited to each
  • Preservation of desirable plant material, especially true native plants, and thinning or removal of undesirable plants (it pays to have a landscape architect decide which is which)
  • Providing reasonable and attractive ramps or slopes up to the home’s entrances, for accessibility.

Solar Access

Site planning should take solar access into consideration. With solar access, builders can incorporate passive space heating and daylighting. These features can significantly reduce energy needs and can contribute to occupant comfort. Over the years, developers and builders have come up with flexible ways to guarantee that homes have access to the sun for the life of the building. Of course, it is not possible to always provide optimum solar access, so it is important to carefully assess shading patterns to make the best compromise. Subdivisions that have streets running within 30 degrees of east-west will have building lots that face or back up to south, which is best for sun control. Subdivisions that have existing north-south streets can consider adding east-west cul-de-sacs.

In northern climates, taking full advantage of solar energy in the design of a home tends to stretch out the house’s form in the east-west direction so that most living spaces can be on the south, with service spaces such as bathrooms, garage, storage, and corridors on the north, and with few east and west windows. In southern climates, the same approach to home design applies, because it is easier to control sunlight on a south-facing facade than on one facing east or west. But additional attention must be given to the use of overhangs and landscaping for shading during the cooling season.

Storm Water Management

Storm water is defined as precipitation that does not soak into the ground or evaporate, but flows along the surface of the ground as run-off. The management of storm water involves a combination of strategies to reduce both the run-off and the amount of pollutants that enter the run-off. Federal and state regulations require most construction sites to manage any storm water leaving the site. Typically the site operator will be required to obtain a permit to discharge storm water from the site. Check with the U.S. EPA or your state environmental agency. A storm water analysis will include soil analysis, topography mapping, peak flow calculations, and run-off characteristics. It will also help measure pollutants such as fertilizers and other lawn treatments, as well as vehicular pollutants. Important aspects of managing storm water run-off include:

  • Minimize land disturbances on the site.
  • Preserve existing topography, vegetation, and landforms as much as possible.
  • Separate impervious surfaces with turf, vegetation, or gravel to increase filtration and reduce run-off.
  • Use pervious paving materials and avoid curbs where possible.
  • Use grass paving systems as an alternative for driveways, streets, and alleys.
  • Minimize the amount of road salt, animal waste, and vehicle fluids.
  • Avoid using pesticides and fertilizers on landscaping.
  • Switch from channeling and paved drainage ways to systems that encourage sheet flow, thus reducing the need for expensive storm water piping.
  • Use open grass swales, pervious paving materials, and natural vegetation to reduce the total hard paved areas in a development.
  • Ensure compliance with local and state drainage master plans and sediment control requirements.
  • Remove or isolate any hazardous material on the site to prevent it from getting into the storm water run-off.