Safe, Affordable, Effective Retrofits

Project Purpose: This effort focuses on testing retrofit wall assemblies with vapor open exterior insulation. The potential wall configurations chosen are based on the findings from the initial project work that included hygrothermal modeling and contractor feedback on cost of construction (see,
Project Abstract: A common retrofit technique for residential buildings in Alaska is the addition of foam board insulation on exterior walls. This popular retrofit is typically performed as part of a residing project for a house. Adding exterior foam board insulation to reduce heating demand can also change the moisture flow through the wall. This change in moisture dynamics is typically not considered in the design or is misunderstood. This is significant because retrofit designs can potentially result in compromised indoor air quality and reduced durability of the structure due to moisture accumulation in the building envelope. Best practice retrofit guidance considers both energy savings and moisture management, but such retrofits are almost never done due to the high cost of construction and impracticality in implementation. For example, when retrofitting a 2x6 wall following the moisture-safe rule of thumb for Fairbanks (1/3 R-value inside the sheathing 2/3 outside the sheathing), eight to ten inches of exterior foam insulation would be necessary. Resistance to installing this amount of exterior insulation has led to a pattern of insulation practices that may meet initial cost savings objectives but introduce risks associated with inadequate moisture control. CCHRC recently completed a project looking for potential alternatives to exterior foam board retrofits. This project was designed to identify affordable wall retrofit ideas that do not compromise the wall durability and that are effective at improving the thermal performance of the envelope. The project found that more vapor permeable exterior insulations can meet the three of the criteria of affordable, effective and safe. Preliminary hygrothermal models pinpointed certain wall designs that require further testing to determine if their moisture performance is acceptable or not. This follow up study will use CCHRC’s Mobile Test Lab (MTL) to test these wall configurations for moisture performance.
Project Keywords: Cellulose Insulation; Energy; Energy Efficiency; Envelopes; EPS insulation; Fiberglass Insulation; Foam Board Insulation; Insulation; Mobile Test Lab; Retrofits;
Project Site / Location: Fairbanks, AK
Project Start: Aug 01, 2017
Project End: Jul 01, 2019
Data Management Plan: Click to download data management plan

Data Set NamePeriod
Wall 3 hourly   Aug 24, 2017 - Jul 15, 2019  
Wall 4 hourly   Aug 24, 2017 - Jul 15, 2019  
Wall 5 hourly   Aug 24, 2017 - Jul 15, 2019  
Wall 6 hourly   Jan 01, 1970 - Jan 01, 1970  
Wall 7 hourly   Jan 01, 1970 - Jan 01, 1970  
Wall 8 hourly   Aug 24, 2017 - Jul 15, 2019  
Wall 9 hourly   Jan 01, 1970 - Jan 01, 1970  
Daily MTL Walls   Oct 21, 2017 - Jul 15, 2019  
Hourly MTL walls   Oct 20, 2017 - Jul 15, 2019  
Wall 1 hourly   Jan 01, 1970 - Jan 01, 1970