This report provides a dataset and analysis of airtightness measurements for low-rise (1 to 3 storey) and mid-rise (4 to 6 story) residential Insulating Concrete Form (ICF) buildings provided by ICF Manufacturers Association (ICFMA) members and published studies.
Published airtightness data indicates that typical Canadian houses are on average better than 4 ACH50 and US houses better than 5 ACH50. The average airtightness of 49 ICF houses collected from ICFMA for this study was found to be 1.26 ACH50. This is significantly better than the performance expected for typical wood frame housing.
The potential for decay of air barrier systems in modern wood framed houses has not been well studied to date. However, ICF walls are expected to have a long-term airtightness performance benefit over loose-laid house wrap air barriers in that they are rigid, strong, durable, and continuous in the field of the wall.