January 23, 2009

As most people know, the latest trend in construction is green or environmentally friendly buildings. As energy prices continue to soar and global warming attracts more attention, the green construction trend is likely to escalate. The goal of this paper is to provide a brief overview of the benefits of green construction and illustrate how off-site construction and modular buildings complement green construction.

Over the last several years, various green projects have been designed and constructed; therefore, customers and contractors are familiar with the concept. Many users are initially interested in obtaining the U.S. Green Building Council’s LEED® certification; however, there are numerous other tangible benefits that can be obtained by using green construction:

1. Reduction in energy/utility consumption
2. Superior interior environment through noise reduction and improved air quality
3. Use of reclaimed/environmentally conscious materials for sustainable construction
4. Reduced/easier maintenance

Reduced Energy and Utility Consumption
Energy/utility consumption can be reduced directly and indirectly through improved energy efficiency. Direct reduction techniques include:

1. Rainwater harvesting for use on landscaping
2. Daylighting (large windows, tubular skylights) to decrease the need for artificial lighting
3. Photovoltaic panels for supplemental electricity generation
4. High R value insulation at the building envelope to decrease HVAC loads
5. Operable windows to allow natural ventilation on temperate days
6. Cool roof systems to reduce heat transfer and reduce HVAC loads
7. Door/window HVAC interlocks that shut off HVAC system when doors/windows open for extended periods of time
8. Deciduous shade trees to prevent heat gain during summer months
9. Dual pane windows with low E coating to reduce infrared radiation transfer and HVAC load
10. Cool operating fluorescent bulbs to reduce HVAC loads

Indirect energy consumption focuses on using energy/utilities more effectively and reducing waste. Improvements in efficiency include:

1. Energy management systems (motion sensors, timers, programmable thermostats, integrated home systems)
2. High-efficiency appliances (Energy Star rated) and HVAC systems
3. Dishwashers and clothes washers that consume less water per load
4. Compact fluorescent light bulbs
5. Lighter colors to reflect more light within building
6. Hanging pendent light fixtures combined with high reflectance ceiling covering

Each aspect has numerous components and can be utilized in conjunction with one another. It is important to keep in mind the prerequisites must be met if LEED® certification is the goal. The time required to recover the initial cost depends on size and location of the structure and individual consumption patterns, as well as materials incorporated.

Superior Interior Environment
In addition to reducing energy costs, green construction should also provide a superior interior environment. Materials such as carpet, cabinetry adhesives, paint and other wall coverings with no or low levels of volatile organic compounds will release less gas and improve the indoor air quality. HVAC systems with noise dampening ducting and isolation systems will reduce the interior noise. Daylighting can also improve the interior quality by boosting the occupant’s mood with natural light.

Use of Sustainable Resources
The use of recycled/reused materials helps to ensure the sustainability of resources. If virgin raw materials are used for every new building project, these materials will eventually be exhausted. As raw materials become scarce, the prices will rise and/or the materials will no longer be available. This trend has already begun as some raw material such as clear heart Redwood is no longer available and must be obtained recycled from existing projects. Recycling/reusing helps ensure that materials will be available for future projects.

Reduced Building Maintenance
The final aspect of green construction is reduced/easier maintenance. Reducing maintenance activities such as painting saves the materials needed but also the waste and environmental impact of the painting such as VOC gas release and water used in cleanup. New, longer lasting materials are now available that need less frequent maintenance. Such materials include cement-based exterior siding that does not require painting and recycled composite decking that resembles wood. Other products facilitate repair and replacement such as carpet tiles that allow individual sections to be exchanged without having to replace the entire floor surface. Carpet tiles also reduce waste during the installation process.

Off-Site Construction is Green
In parallel to this greater acceptance of green is the growth in the off-site construction process and improved perception of modular buildings. Modular buildings and off-site construction are similar, but off-site construction commonly refers specifically to permanent buildings versus modular buildings that can be either permanent or relocatable. Green features are available in all modular buildings but are considerably more common in off-site construction due to the permanent nature. In recent years, off-site construction has advanced and numerous innovations are now available. Such innovations include more efficient production facilities, superior transport systems, creative architectural designs and new engineering technologies providing greater flexibility.

Off-site construction merges well with the concept of green construction for a variety of reasons. The centralized construction location allows for much greater reuse and recycling of material as a set collection schedule and policies can be established. Material waste due to weather damage is decreased as the construction process occurs in weather protected facilities. Wastewater is easier to control and collect as production facilities are paved and sloped to a collection area. Traffic and air pollution is reduced as workers drive shorter distances to the factory versus traveling to various jobsites. As materials for multiple jobs can be purchased in bulk quantities and delivered to a central location, the cost of materials and number of deliveries can be minimized. Off-site construction uses the same materials and designs as site built construction allowing for easy incorporation of green materials and designs.

Progressive builders and architects view off-site construction to be an integral part of the green construction movement, and the interest in green off-site construction has grown tremendously as green is integrated into more diverse buildings.