The Green Target is a visual tool that helps analyze the sustainable properties of a stone project. Color coded pie wedges score four qualities of sustainability for any given project. The graphic is quick and clear and easily understood by everyone. The tool is meant to promote dialogue as well as encourage stone masons and wallers to challenge themselves to seek ways to improve the sustainable attributes of their work.
I broke sustainability out into four categories. They are equally weighted in the tool, to ensure that important parts of the conversation aren’t ignored. I believe that the carbon footprint of a project is a crucial concern, but not the whole picture. The outer ring is red, indicating a lower overall rating in any category. The inner ring is green, indicating that the project scores well in terms of sustainability. The middle ring is yellow indicating a neutral rating or inconclusive information. Scores in the red and yellow should prompt further inquiry and planning, to discover ways to reduce the footprint and boost the sustainable characteristics of the project. The categories are:
Does the stonework serve a functional purpose or is it purely decorative? Is it necessary? Are the properties and benefits of stone utilized in some meaningful way? This category will draw the most debate, as a great deal of the stonework done in modern times is purely decorative and will tend to score poorly. This tool isn’t meant to discredit any category of stonework, but it is meant to raise tough questions and seek lower impact alternatives. A stone retained heat oven would score well, a four inch veneer on a wood frame house would not.
What is the environmental impact of the project? What is the embodied energy cost or carbon footprint of the project? This includes the sourcing of all materials, freight and installation. Carpooling to work and building with lime mortar improves the scoring here. Using Pennsylvania Bluestone in North Carolina does not.
How long will the work last? How much maintenance will be needed under fairly typical usage or conditions? A well built drystone retaining wall should score well. The four inch veneer of face bedded stone would not.
What does the work contribute to the community? Are local craftspeople and merchants being used? Is it a public or private project? Does it advance the craft? Does it educate people? Consider this category over the likely lifespan of the work. A public stone installation scores higher than one in a gated community. Oddly enough, cultured stone does not rate at all in the Culture category.
The tool can be used to rate an existing project, but its best applicaion is in the planning stages of new work. Score a few scenerios to help choose a lower impact project that contributes to the world.
Quick Case Study: Stone Cabin
I designed this cabin and built it with Fred Lashley of the Unturned Stone during my time working there. It is structural stone with two foot thick walls and uses lime mortar. It scores well in most categories, but consumed vast quantities of energy, despite the lime based mortars. See the detailed case study for an explanation why.