Examples: Advanced Framing Reused Wood Straw Bale Structural Insulated Panels		Many commercial buildings are steel framed or built from masonry block. By contrast, over 90% of the houses built in the United States are wood framed. Even when these typical structural wall systems are used, there are ways to improve their environmental performance through efficient design and thoughtful product choice. On other projects, it may be possible and desirable to break away from conventional materials and adopt an alternative wall system with particular environmental benefits. For example, a system with a high recycled content, or a lightweight engineered system, one that reuses materials from an existing building, or one made from rapidly-renewable materials or even the earth of the building site itself could be selected. Alternative wall systems like insulating concrete forms and structural insulated panels are reporting significant increases in their market share, while straw bale building is also finding ever wider popularity. It's fortunate that there are so many wall system options, because there are so many different building projects, and a system that is ideal for one may be nearly a disaster for another. Choosing the best wall system represents a careful balance between the environmental attributes of various systems and the circumstances of the building project. Aside from the question of whether a particular system is climate-appropriate on the large scale is the question of whether it is suited to a neighborhood and a specific lot. For example, thick-walled indigenous building systems may be a poor choice for today's small urban and suburban lots. Another consideration involved in the selection of an alternative wall system is the amount of labor involved in both installation and maintenance. Frequently alternative wall systems that are inexpensive in terms of materials turn out to be very expensive indeed in terms of both their skilled and unskilled labor demands. While this may be a highly desirable tradeoff for owners willing to invest sweat equity in their projects, in other cases it can lead to skyrocketing project budgets and expensive construction delays. Finally, it's important to realize that the ramifications of choosing an alternative wall system extend far beyond the design and construction process. To begin with, selecting an unconventional wall system may require a large time investment in persuading code officials to permit the project. Similarly, the project owners may experience challenges in finding a lending institution and an insurance company willing to cover a house built from alternative materials. Later, owners may face challenges in finding compatible finishes, as well as unusually high maintenance requirements for an alternative system. They should also recognize that repairs may require the rare talents of someone skilled in the particular building system. It's good to be aware of these potential pitfalls from the very beginning of the project, so that the time and effort to circumvent or overcome them can be factored into the wall system decision. At the same time, realistically recognizing the challenges of an alternative structural wall system shouldn't be allowed to overshadow the aesthetic, performance and environmental benefits that such systems can offer. Carefully consider the options available in light of their environmental merits, to arrive at a decision on the best wall system for your particular project. Go to wall system examples