Project Overcoat - An Exploration of Exterior Insulation Strategies for 1-1/2-Story Roof Applications in Cold Climates

Airtightness Results of Roof-Only Air Sealing Strategies on 1 �-Story Homes in Cold Climates

“…In 2012, the NorthernSTAR Building America Partnership began exploring alternative methods to find long-term solutions to energy loss in 1 ½-story homes to save energy, improve comfort, and reduce the risk of ice dam formation/reformation. Project Overcoat: An Exploration of Exterior Insulation Strategies for 1 ½-Story Roof Applications in Cold Climates (Ojczyk et al 2013) determined that the External Thermal Moisture Management System (ETMMS) approach warranted further evaluation as a roof-only approach for maximizing opportunities for insulation, air sealing, and roof deck ventilation.…”

“…The previous BA report (Ojczyk et al 2013) indicated that there is contractor interest in using a roof overcoat process to mitigate ice dams. The same study, however, pointed to the lack of design details and supporting data for roof-only ETMMS approach.…”

“…Many approaches to ice dam mitigation have been in tried in the past including: (1) interior-applied improvements to insulation and air sealing, (2) roof raking, and (3) heat tapes. In the Building America (BA) report Project Overcoat: An Exploration of Exterior Insulation Strategies for 1 ½-story Roof Applications in Cold Climates (Ojczyk et al 2013), it was estimated that there are several million 1 ½-story homes in cold climate states nationwide. Homeowner desire to expand living area into unused attic space, however, has resulted in less than optimal conditions for providing energy efficiency, comfort, and long-term durability.…”

“…In a previous BA report (Ojczyk et al 2013), the NorthernSTAR BA partnership team explored different exterior roofing strategies for existing 1 ½-story homes. The overall intent of this study was to determine which exterior overcoat approach warranted further evaluation as a roof-only approach for maximizing opportunities for insulation, air sealing, and roof deck ventilation to yield reduced air exfiltration and heat loss as well as the mitigation of ice dams.…”

“…The previous BA report (Ojczyk et al 2013) included interviews with six contractors in cold climate states that had experience using exterior overcoat solutions as part of whole house or roof-only energy improvements and/or ice dam mitigations. The builders commented that their preferred method to mitigate ice dams and improve energy performance was the exterior overcoat method.…”