Charrettes can be used for any scale of planning or design project. They have been used for projects ranging from regional planning to building design.
For large projects that have distinct geographic and/or political boundaries it is common to hold a single regional charrette or workshop to work on shared values or vision elements, followed by several smaller local charrettes to work on the local issues under the larger vision, perhaps concluding with another regional workshop. A benchmark of whether a project is too big for a single charrette is whether or not enough stakeholders can be expected to participate throughout the charrette. When most of the issues are outside of a person’s area of interest it can be very difficult to get his or her sustained involvement.
For instance, regional issues such as ground water treatment may be of interest to many and a regional workshop to gain consensus on the importance of this issue may attract people from throughout the region. When you begin to address possible design solutions the issue can become very local. People from rural areas may not be interested enough in urban solutions to come to three charrette meetings. They may, however, come to three meetings about the impacts of agriculture on streams. It is true that the two issues are part of the same problem. That connection between the rural and urban solutions and the issue of regional water quality can be made at the regional workshop level.
A related question is whether or not a charrette can have too many participants. The answer is generally no, provided that there is adequate space and enough staff members to manage and facilitate the meetings. Charrettes with large numbers of stakeholders do tend to be longer if only to accommodate the number of scheduled meetings required. More days also provide flexibility to handle the inevitable unexpected issues that usually call for more initially unscheduled meetings.
On the smaller scale, charrettes can be used for the design of a single building. This application is appropriate when it is a complex design problem and/or politically charged project. The design of a building under a new zoning ordinance which allows taller buildings is likely to face a complex political environment for which a charrette is a good tool to involve the community. Charrettes are also commonly used for green building design where there are no political issues. The complexity of green building design requires an approach that integrates the efforts of many stakeholders and design professionals with disparate views. The charrette is an effective tool for facilitating integrated design.