Thermal Blocks . Thermal insulated blocks are made of concrete consisting selected aggregate and cement with extruded or expanded polystyrene. The polystyrene is specially designed and placed symmetrically during the time of molding the blocks at wet stage of concrete. Bucomac thermal blocks specifications: high load bearing, fire resistant, excellent sound insulation and high thermal efficiency. Thermal Values for our blocks U value: .362watt/m2 C K value: .0723 watt/m2 C R value: 2.762 m2 C/ watt Thermal Blocks Sizes Size 1: 400 X 250 X 200 mm Size 2: 400 X 200 X 200 mm