Safe Effective Affordable Retrofits
CCHRC is continuing to advance durable, low-cost options for retrofitting homes. In searching for an alternative to exterior foam board retrofits, we found that more vapor permeable exterior insulations could offer a more affordable option. This study uses our Mobile Test Lab to test several wall configurations for moisture performance.
1. Our latest study of wall retrofits suggested that using cellulose as exterior insulation instead of foam board allowed for better moisture control within the wall. Because cellulose is more permeable to water vapor than foam, it is less likely to trap moisture in the wall.
2. Another retrofit approach includes air sealing the wall sheathing by adding an air barrier without adding any exterior insulation. This wouldn't improve the R-value of the wall but would be less expensive than a full exterior insulation retrofit (such as the REMOTE wall) and would still save energy by reducing air leakage.
Both retrofit approaches avoid trapping moisture in the wall assembly while aiming to reduce the cost and complexity of retrofits.
This project will establish more background on these approaches and lead to new wall studies and retrofit reccomendations. It includes a literature review, modeling and interviews with contractors. A summary will be shared with stakeholders and inform future retrofit experiments.
Read the report here.