Some Considerations of Sustainability...

... in Site Work, Excavations, and Foundations

Site Selection 

• Buying and renovating an existing building rather than building a new one saves a great deal of building material. If the existing building has been scheduled for demolition, it also avoids dumping an enormous quantity of material into a landfill.
• Building on a  damaged site, and designing the building so that it helps to restore it, benefits the environment rather than degrading it.
• Building on agricultural land takes that land out of production forever.
• Building in forests and on wetlands and prairies destroys wildlife habitat.
• A building that is well connected to existing networks of public transportation , and to pedestrian and bicycle paths, pays environmental dividends every day for the life of the building by saving fuel, reducing air pollution from automobiles, and minimizing commute times.

 Site Design

• Large existing trees cannot be replaced except by growing new ones, which takes many decades. Planting of new trees is always a good thing, but preservation of existing trees is even better.
• Distinctive site features such as rock formations, forests, grasslands, streams, marshes, and recreational paths and facilities, if destroyed by construction, can never be replaced.
• Protection and enhancement of the health of ecosystems such as marshes, lakes, forests, and prairies is essential to the maintenance of biodiversity.
• Grading the site to appropriate slopes and planting vegetation that holds the soil in place will prevent erosion.
• A drainage system that conducts water to areas on the site where it is absorbed into the earth works to replenish natural aquifers and avoids overloading of storm sewers.
• Building above the water table helps avoid disturbance of aquifers.
• A new building that shades adjacent buildings deprives them of natural illumination and, in many cases, useful solar heat. The result is an increase in the amount of electricity and heating fuel used by the shaded building.
• Siting a building for best exposure to sun and wind maximizes solar heat gain in winter and minimizes it in summer to save heating and air conditioning fuel. It also allows utilization of daylight to replace electric lighting.
  
  
• In general, a building should be designed in such a manner that the site does the heaviest work of environmental modification through good orientation to sun and wind, trees that are placed so as to provide shade and windbreaks, and use of below-grade portions of the building for thermal mass. The passive shell of the building can do most of the rest of the work through orientation of windows with respect to sunlight, good thermal insulation and airtightness, utilization of thermal mass, and tight multipane windows. The active heating, cooling, and lighting equipment should serve only to fine-tune the interior environment, using as little fossil fuel and electricity as possible.
 

Construction Process

• It is essential to protect trees and sensitive areas of the site from damage during construction.
• A building should comply with all local conservation laws relating to soils, wetlands, and stormwater.
• Topsoil should be stockpiled carefully during construction and reused on the site.
• It is important to guard against soil erosion by water and wind during construction.
• Vehicle tires compact soil so that it cannot absorb water or support vegetation. Thus, it is important to develop minimal, well-marked access routes for trucks and construction machinery that minimize soil compaction, as well as minimizing noise, dust, air pollution, and inconvenience to neighboring buildings and sites.
• Construction machinery should be selected and maintained so that it pollutes the air as little as possible.
• Surplus excavated soils should be reused either on the site or on another site nearby.
• Construction wastes should be recycled as much as possible.

What is sustainability?