Eco-Efficiency Analysis of Wall Cladding Systems
Eco-Efficiency Analysis is a tool that has been developed by BASF to compare the life cycle cost and environmental impact of products that provide a defined level of customer benefit. This methodology has been validated by TÜV Berlin and most recently by NSF International under NSF Protocol P-352.
This study involved comparison of wall assemblies that employed brick, stucco and a water-drainage exterior insulation and finish system (EIFS) claddings over a projected 50-year service life. All wall assemblies utilized steel stud/gypsum sheathing construction and were equally insulated to a U-factor of 0.077, so that building energy consumption was held constant. Comparisons were made of the walls assemblies themselves. All wall designs, material quantities, material costs, labor costs, maintenance requirements, maintenance costs and final disposal costs were provided by RS Means. Information provided by RS Means was used to compare the life cycle costs and environmental impacts of the three cladding systems.
Environmental impacts were comprehensively assessed in six areas – Energy Consumption, Emissions, Toxicity Potential, Occupational Illnesses and Accidents, Resource Consumption and Land Use. The brick wall assembly was found to create the greatest environmental burden in each category, with stucco providing substantially less environmental burden and the EIFS assembly providing the lowest burden of all, by a significant margin. In large part this was due to the much lower amount of material needed to construct and EIFS wall assembly – 6.2 lbs/SF for EIFS compared with 17.8 lbs/SF for stucco and 46.0 lbs/SF for brick.
Life cycle cost of the brick wall assembly was also the highest of the three, by a significant margin. As such, the brick wall was found to be the least eco-efficient of the three. Life cycle costs of the stucco and EIFS walls were similar enough that local cost factors could swing cost rating one way or the other. When combined with environmental burden, the EIFS wall assembly was found to be the most eco-efficient.