11.2 Sustainability and buildings  (Page 3/10)

The demolition of old buildings to make way for new and construction projects themselves generate huge amounts of waste. Careful deconstruction    of buildings allows for reuse of materials in future construction projects or for recycling of materials into new building (and other) products. Deconstruction creates economic advantages by lower building removal costs due to value of materials and avoided disposal costs, reduces impact to site on soil and vegetation, conserves landfill space, and creates jobs due to the labor-intensity of the process.

A 1998 EPA study of building-related construction and demolition (C&D) debris generation in the U.S. found that an estimated 136 million tons of building-related C&D debris were generated in 1996, the equivalent to 2.8 pounds per person per day. 43% of the waste (58 million tons per year) was generated from residential sources and 57% (78 million tons per year) was from nonresidential sources. Building demolitions accounted for 48% of the waste stream, or 65 million tons per year; renovations accounted for 44%, or 60 million tons per year; and 8 percent, or 11 million tons per year, was generated at construction sites.

Even when deconstruction is not possible, the waste can be recycled by sorting the materials after they are collected and taken to a waste transfer station. Since new construction and renovation requires the input of many materials, this is an opportunity to utilize products that enhance the sustainability of the building. These products may be made of recycled content, sustainably grown and harvested wood and pulp materials, products that have low emissions , and products that are sourced locally. These products enhance the sustainability of the building by supporting local economies and reducing the fuel needed to transport them long distances.

Energy-saving building features

Energy efficient measures have been around a long time and are known to reduce the use of energy in residential and commercial properties. Improvements have been made in all of these areas and are great opportunities for further innovation. Green buildings incorporate these features to reduce the demand for heating and cooling.

Insulation

The building should be well insulated and sealed so that the conditioned air doesn’t escape to the outside. Insulation can be installed in floors, walls, attics and/or roofs. It helps to have more even temperature distribution and increased comfort as well.

High-performance windows

Several factors are important to the performance of a window (see Figure A High-performance Window ):

• Thermal windows are at least double-paned and vacuum-filled with inert gas. This gas provides insulation
• Improved framing materials, weather stripping and warm edge spacers reduce heat gain and loss
• Low-E coating block solar heat gain in the summer and reflect radiant heat indoors during the winter

Sealing of holes and cracks

Sealing holes and cracks in a building’s envelope    as well as the heating and cooling duct systems can reduce drafts, moisture, dust, pollen, and noise. In addition, it improves comfort and indoor air quality at the same time it saves energy and reduces utility and maintenance costs.