How is thermal bridging prevented?
The construction process of our home, in southeast Iowa, was completed in January 2014. The house has fiber cement lap board siding and an interior spray foam insulation. In March of 20014 we noticed moisture accumulating, in a vertical line pattern, on the east elevation of the house.
After our contractor failed to honor the home warranty, we contacted the fiber cement board manufacturer, to determine the cause of the problem. Based on the photos we provided, we were told the siding was installed incorrectly and there is a thermal bridging problem. A supervisor with the siding manufacturer also reported the blown on interior insulation is also a problem. Based on the manufacturer’s suggestions we hired a home inspector, certified by the American Society of Home Inspectors.
The inspector has extensive experience with this manufacturer’s fiber cement lap board siding. We were told the following: 1) the fiber cement board lap siding was installed incorrectly and a number of required flashings were not installed at all, 2) the siding needs to be installed to manufacturer’s specifications, 3) because the house has spray foam insulation it is very tight and cannot breath, and 4) the inspector suggested getting the HVAC system balanced and bringing in fresh air into the house through the use of a ERV or HRV system (the HRV system was reported as the preferred system).
We have been trying to get a qualified HVAC contractor to perform the HVAC load balance analysis for several months; however, those qualified are too busy so we continue to wait. We have been told not to install an ERV or HRV until the results of the HVAC load balance analysis is completed.
Experienced fiber cement board siding installers from Des Moines, Iowa have been contacted and requested to provide a price for the correct installation of the siding; however, they put us off. There appears to be some other issue/s of concern; however, they do not say what it is.
All elevations of the house are now affected by the thermal bridging.
Question 1: Does the fact the house cannot breathe, the HVAC system is not balanced and the house is insulated with spray foam insulation affect the thermal bridging?
Question 2: What are your recommendations to the thermal bridging problems?
Thank you for your kind response.
S. (Southeast Iowa)
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