Poorly insulated knee wall spaces leave homeowners experiencing cold, drafty rooms in the winter and hot rooms they can never seem to cool down in the summer. Often, the only protection between a knee wall space and the living space is fiberglass insulation in the knee wall. However, it's ineffective because it's almost never closed in on all sides, provides no air sealing, and when knee wall spaces are home to ductwork, it doesn't help protect the ductwork from extreme temperatures.
In these cases, we insulate the attic rafters and gable ends of the knee wall space with closed-cell insulation. This helps to reduce the extreme conditions in the knee wall space that impact the living space making it uncomfortable by reducing the conditioned air loss from the living space to the unconditioned attic knee wall space and the heat transfer from the attic space into the living space.