Insulating a Knee Wall in Alexandria, VA

A kneewall space is created when a finished room is built within a sloped roof. A short wall called a "kneewall" forms a triangular space which in this case, is accessible with a short door. Cold and hot air from outdoors enters the kneewall space through leaky fascia/soffit assemblies or through soffit vents. Kneewalls that are not properly insulated can contribute to your top floor being very uncomfortable. Here, a kneewall is air sealed and insulated with closed cell spray foam. SilverGlo insulation foam board is also installed on all vertical walls between levels.