Abstract: The multi-ply panel for forming or adding to a wall, floor, or ceiling, or for the inclined surface of a building includes a stack of layers. At least one layer is formed of parallel structural strips, preferably made of wood. Filler strips are placed between the structural strips and made of a different material than that of the structural strips. The materials may be selected for the heat or sound insulation properties, thermal inertia, or fire-resistant properties thereof. At least one rigid filler strip is made of an insulating material with heat conductivity less than 0.038 W/m·K.