Air Infiltration Testing

Shortly after the completion of a 9,000 sq. ft. multi-level log home, the inability of the HVAC system to effectively heat and cool the home was discovered. Previous investigations by others revealed numerous sources of air leakage. Some of these sources were addressed. However, further evaluation was needed to address the source and extent of remaining air leakage.

In addition to air leakage problems, several water leaks were reported. Some of these water leaks were attributed by others to inadequate window and door details. CTLGroup's services were requested to provide quantifiable air infiltration data.

CTLGroup proposed to quantify the air leakage so that the relative effectiveness of repairs could be measured and quantified. CTLGroup's scope of work included document review and a field investigation including conducting air infiltration testing on the building envelope in substantial accordance with ASTM standard Test Method E 779 for Determining Air Leakage Rate by Fan Pressurization (The Blower Door Test).

The testing revealed excessive air leakage occurring at all exterior doors, as well as between the window frames and the adjacent log siding. Of particular interest in this building, air leakage was also observed entering the residence through the cracks in the log siding. Many of the checks and cracks in the logs did not pose a structural problem. However, they would allow significant volumes of air leakage through the exterior fa├žade. Additional air leakage was revealed entering the building through the debonded joint between the log-and the chinking. Air infiltration rates of over 10 times the estimated natural infiltration were measured by the testing.