Optimization is a major factor that distinguishes green building from ordinary construction. Green building focuses on making the best use of resources during all stages of construction. The goal is to maximize the site’s natural resources and provide a healthy space for building occupants, while minimizing the resources used. To accomplish that, a green building project typically involves a more detailed planning process.
Successful green building requires builders to maintain a big-picture view of the project even while immersed in the smallest details. It also often requires a higher degree of coordination with subcontractors and other entities involved in the construction process. If a builder wants any type of green certification, documenting the planning is essential. While the extra planning required to build green may add to building costs, some of the methods we’ll discuss may actually decrease the costs of the overall building project.
Builders reduce framing quantities using the principles of Optimum Value Engineering (OVE), which removes redundant framing components without compromising a structure’s integrity. You can see a commercial example of this technique in the new Hearst Building in New York City, where rethinking the way the frame of a building is constructed allowed engineers to use 20 percent less steel than a conventionally framed steel structure. In residential structures, simply aligning floor joists and roof rafters to bear directly on wall studs can help a builder reduce the amount of framing in walls. Other waste-saving methods include careful excavation of only necessary areas to minimize disruption to native soils and saving plants and trees near the structure to reduce landscaping costs.The most common green building methods are based on very simple ideas, many of which can help to make a building more economical to construct. For example, builders typically design buildings around modules of two and four feet to minimize material waste and to match the common dimensions of building materials. When possible, they order building materials precut to save time and reduce the amount of waste generated on-site. And efforts are made to recycle any waste created on-site.
MAXIMIZING THE SITE
Making the best use of a building site is one of the fundamental tenets of green building. These principles are not new. Colonial-era builders frequently built saltbox-style homes for that reason. The saltbox style is typically characterized as having large, south-facing windows and a small face on the northern side to minimize heat loss from cold north winds.
Positioning the building to take advantage of the sun or prevailing breezes can significantly decrease heating and cooling loads as well as lighting needs. Using existing trees and landscaping to provide shade and windscreens can also contribute to energy savings.
One common green building trend is the use of passive solar heating. Popularized in the 1970s, passive solar heating harnesses the sun’s energy indirectly. Passive heating uses a thermal mass, such as a stone or tile floor, to capture the heat from south-facing windows and release it in the evening when there’s a need for heat. A popular cost-saving approach to passive heating is to forgo the traditional basement or crawlspace with a framed floor above it and instead use a stained, etched, or otherwise “decorated” concrete slab. Advances in concrete finishing allow slabs to look like stone, marble, and other attractive patterns.
Builders can also maximize the use of the site by paying special attention to sizing roof overhangs and planting deciduous trees to decrease summer cooling expenses.
To ensure the longevity of any building, managing the way rain, snow, and air interact with the structure is essential. Proper flashing details, understanding when and where to use vapor barriers, and directing moisture away from a building are all crucial to maximizing the lifetime of a structure and therefore crucial to green building.
Other water-related green building practices include controlling runoff during construction to avoid polluting nearby lakes and streams and planting native or drought-resistant species of shrubs and trees to create a low-water landscape. Capturing rainwater from downspouts or reusing the water from sinks and tubs to irrigate the landscaping will also conserve water.
Using low-flow kitchen and bath fixtures to reduce water consumption at the source and using re-circulating hot water systems are also common green methods, especially in commercial buildings where savings multiply because of the quantities involved.
One of the most common green building methods is using more insulation than building codes require. Insulation has evolved from a seldom-seen luxury to a required part of every home. There are many types of insulation now available, including traditional fiberglass and cellulose, but methods including sprayed-on polyurethane foams, polystyrene sheets (styrofoam), and natural fibers derived from wool or cotton are becoming more common. While using more insulation helps to save energy, it is important to consider how the insulation will behave as part of the wall system. A properly detailed wall with a minimum of insulation that doesn’t allow condensation is vastly superior to more insulation in a wall that will rot in a few years.
On the roof, radiant barriers or light-colored roofs will reflect much of the sun’s energy rather than letting it penetrate the structure. That will increase energy savings for residential and commercial structures alike.
Many green building methods are based on age-old building principles reinvented thanks to advances in building technology and materials. New ways to take advantage of the sun, better ways to insulate the structure, making the best use of building materials, creating a building where the components work in harmony and are balanced with other components, and many other techniques are all tenets of green building methods. While employing those methods takes careful planning and execution, potentially increasing building costs during planning, some of the methods can actually reduce building costs and save on energy consumption and costs in the long run.