Evaluation of suitability for passive retrofit of wooden roof considering the specificity of historic buildings

Abstract

Energy consumption and carbon emissions of buildings must be reduced according to the 2030 carbon neutrality policy. Many aspects of historic buildings should be considered in their improvement because of their historical value. Thus far, a new strategy to lower energy consumption and improve energy performance is required. This study intends to derive an optimal energy efficiency package to reduce the energy consumption of historic buildings. To accurately analyze energy efficiency, the condition of a historic building was evaluated through on-site inspections. The roof retrofit technology scenario was used to reduce energy loss in exposed rafters. The exterior of the building cannot be damaged as it has historical value. This retrofit technology was analyzed to determine the energy-saving effect and economic feasibility of the package to derive the optimal solution. Retrofit techniques were individually analyzed and packaged for the effective preservation of historic buildings. This study compared a total of six scenarios by combining three types of insulation materials, based on the location of internal insulation, to protect the exposed rafters. Considering energy-saving, economic feasibility, and damage weight, the scenario where polyurethane insulation was applied between battens was the best. However, the insulation of the roof must consider fire resistance as per the Building Act of the Republic of Korea. Considering flame-retardancy, the scenario in which glass wool was applied between batten was the best for the target building.