Evergreen Construction

Green Building and Social Responsibility

Many people wish to live in homes that have reduced adverse impact on human health and the natural environment. The green building movement is responding this desire. However, there is no concise or unambiguous description of the specific attributes of green building. There are ongoing discussions among builders, building scientists, ecologists and urban planners about what constitutes a green building material and how to design and build green homes.

In the Pacific Northwest where I work some of the most visible green building efforts are the Built Green program and the Northwest Ecobuilders Guild. On a national level the US Green Building Council has developed the LEED system (Leadership in Energy and Ecological Design) for commercial structures but has not yet completed a program for residential construction. Yet despite these and other developing programs, there is currently limited consensus about what constitutes best green practices.

Ironically, well-intentioned designs that focus too closely on a few easily-measured benchmarks of perceived greenness can yield houses that have greater overall negative environmental impacts than carefully designed and built ‘traditional’ homes. Real green design must consider material and energy costs over the entire life cycle, as well as hidden costs absent from standard economic accountings.

There are, however, several unequivocally green principles that can be followed in the remodel and construction of homes. Many are obvious; most were familiar to our grandparents. All apply to design as well as construction. At the core of each lies the fact that no structure is green if it is short-lived.

Site the house well. Use overhangs, natural topography, careful window placement and daylight basements to optimize solar heat gain (usually in the morning and during winter), to buffer nighttime heat loss, and to shield the structure from wind.
Don’t waste. A smaller, well-designed, carefully detailed space often works better than a larger space. Remodel and reuse materials where practical. Dispose of as little material as possible. Nothing is green in a landfill.
Build it right. Design a structure that will remain useful even as families and times change. Employ time-tested building systems, use durable materials, and build with craft and care. Handsome, well-built homes are respected and maintained, and can stand for centuries. Ugly, poorly built boxes may not last a generation.
Mind the details. Most structural and maintenance problems in residential home construction arise from inadequate attention to details associated with controlling liquid water and water vapor. Most comfort problems arise from inadequate attention to details associated with air control and insulation. Getting these invisible details right the first time avoids the expense and waste of later repairs and reduces maintenance costs.
Use locally-produced, sustainable materials wherever possible. There is no green transportation system for building materials.
Respect your neighbors. A house that fits into the neighborhood and complements neighboring homes strengthens the community, increases property values, and engenders the care necessary for a long life. A house that clashes with neighboring homes will eventually be remodeled or torn down.
Beware of fads. Plastic housewrap, vinyl windows and spray-applied exterior paints are among the myriad materials and techniques that are inferior to their traditional counterparts and should usually be avoided.
But be open to new ideas. Air admittance valves, pervious paving, engineered wood products, and modular construction are among the myriad new products and techniques that should carefully be employed.

Applying these general principles throughout design and construction reduces both immediate and long-term adverse environmental impacts of home construction, and produces comfortable, quality homes, with small increases construction costs, and significantly reduced maintenance and long-term costs. Two representative details that are often neglected in modern construction illustrate these general principals.

The first detail is the absolute requirement that all 6 sides of each wooden exterior cladding and trim board be painted before installation. This is easy and cheap if planned for, and increases exterior paint lifetimes from a few years to decades. The second detail is careful attention to stopping convective air movement between walls and unconditioned attics and basements, and to the outside. This is easy and cheap, reduces heating and cooling requirements, and makes houses less drafty and more comfortable. If neglected, it contributes to problems like ice damming, rotten sheathing, and paint peeling.

There are also a growing number of businesses and techniques available that specifically address the issue of decreasing the adverse environmental and health impacts of home building. Many improve the comfort of the home as well. A complete list of these would fill a book, but many of the most useful are simple and inexpensive.

Use a demolition materials recycler, rather than a garbage hauler, to supply a dumpster. Some companies now provide dumpster services that are almost identical to traditional haulers in both service and price, yet rather than taking debris to a landfill they sort and recycle it. Recycling rates often exceed 90%, and the only difference usually apparent to the builder is the prohibition on disposal of treated lumber in the dumpster.
Use a building materials recycler. Recycled building materials sellers have long been a source of hard-to-find and period pieces and materials. In addition, many businesses now also offer free removal of materials such as bathtubs and radiators that they can subsequently resell.
Employ modern, low-tech air control and insulation techniques. Carefully sealing all plate penetrations and sealing exterior sheathing to top and bottom plates (and intermediate blocking) with construction adhesive dramatically reduces loss of conditioned air from within joist bays, increasing the effectiveness of insulation and reducing drafts within the house. Similarly, employ air-tight drywall techniques throughout the interior
Use modern, high R-value, low-e coated glazing in high-quality wooden windows. Seal window frames to rough openings carefully. Task-specific weatherstripping is available which performs well for longer than the expanding foams usually employed for this task
Don’t depend on the user to conserve energy. Use time-delayed and linked switches to automatically control bathroom fans, lights and other devices. Use electronic thermostats with automatic nighttime setbacks. Employ careful lighting design with task lighting and motion-sensitive exterior lighting. Select energy-efficient appliances and lighting systems.
Don’t depend on the user to conserve water. Use modern low-flow toilets and washers, which work as well as or better than their older counterparts. Consider plumbing hot potable water in timer-controlled recirculating loops in heating climates, or employ point-of-use and on-demand water heaters.
Keep water on site. Minimize paving, and discharge downspouts onto the property or into drainage swales rather than into storm drains to lower sewage treatment requirements and increase groundwater recharge. If local codes allow, consider separating greywater (sink and shower) from sewage plumbing, and discharge greywater on-site.
Consider alternative energy supply and waste disposal techniques. Solar-thermal water heaters are today practical and cost-effective in many parts of the country. Photovoltaic and wind-generated electricity remain more costly than conventionally-generated power, but may be cost effective if building off of utility grids. Similarly, ground-source heat pumps and septic sewage systems are often cost effective outside developed areas.
Landscape with native vegetation to provide food and especially habitat for wild animals. Minimize plantings of species that require chemical fertilizers or mechanical cultivation or mowing.