To better understand construction's impact, an overview of building ecology as a concept and as a decision-making model for school systems is provided. "Building ecology" is defined as the interrelationships among people, the built environment, and the natural environment. It has special relevance for school design because most of the users are children; therefore it is important that administrators fully understand the types of materials used in building schools. A material's energy efficiency can be important, as is the lifecycle of any material. A decision-making model is presented, which offers a step-by-step process for determining the best materials to use. How to choose flooring is featured as an extended example of this process. The environmental issues connected with various flooring such as vinyl composition tile, linoleum flooring, carpet, terrazzo, wood flooring, and ceramic tile are detailed. A hypothetical material selection process is offered, along with general recommendations in choosing, installing, and maintaining flooring. (Contains 13 references.) (RJM)