The Perfect Continuous Insulation Plaster System

One of the hardest challenges of the construction community is staying informed on constantly changing materials, systems, techniques and code requirements. One recent change is the code mandated use of exterior continuous insulation to improve the energy efficiency and environmental impact of our building stock. The intent of this paper then is to inform the construction community about strategies that utilize plaster coatings over continuous insulation. We do this with some reservation because we believe the least imposing strategy already exists.

In 2005 the US Department of Energy (DOE), through the Office of Energy Efficiency and Renewable Energy’s Building Technologies Program began a “Wall Cladding Performance Study.” In this landmark 3 year field research project conducted by the Oak Ridge National Laboratory (ORNL) they concluded that Exterior Insulation Finish Systems (EIFS) with Drainage outperformed all other wall materials in terms of moisture management, while maintaining superior thermal performance. The Executive Summary of this study can be viewed and downloaded at

This study it would seem is one of many reasons that point to EIFS with Drainage as the perfect “continuous insulation” plaster system to meet the requirements of Minnesota’s New Energy Code. Other systems, while well intentioned, are often concocted “Frankenstein” facsimiles where the plastering contractor’s experience and insight have been ignored. The unfortunate result is sometimes a contentious one, with finger pointing generally in the direction of the plastering contractor, even though he had no input or control over design decisions.

Arguments that dismiss or disparage EIFS with Drainage today as a defective product for problems that happened twenty years ago are unwarranted and misinformed. Notwithstanding these arguments, it is the opinion of the Minnesota Lath and Plaster Bureau that EIFS with Drainage is the best choice of continuous insulation systems. – The Minnesota Lath and Plaster Bureau, August 2015

“Lex parsimoniae: The simplest answer is often the correct one”

Loose translation; attributed to William Ockham, Scholastic Philosopher (c. 1287–1347)