There are many ways to build an insulated sloped roof. If the studs are covered on the attic side you can insulate the knee wall by drilling a hole in the covering near the top of the wall and filling the cavity with blown insulation. Pin By Jessica Inocencio Gray On Insulation Attic Renovation Attic Remodel Attic Insulation Get your protective clothing dust mask and goggles and grab a light and climb on in there. Best way to insulate an attic knee wall . The first point is sealing the soffit venting. If you dont currently see any signs of moisture accumulation mold or rot there is no need to worry. Two Ways to Insulate Attic Kneewalls Good. In this case after insulating the stud cavities with fiberglass batts use 1-inch minimum rigid foam insulation to cover the back of the knee wall which will prevent attic air from circulating around and through the insulation. Obviously youre going to have to get into the attic to insulate the knee wall. There are two basic ways to ins...