Roof slab PAROC ROS 30g is non-combustible stone wool insulation for use as a load bearing thermal insulation layer of existing and new ventilated flat roofs. The roof insulation slab is developed to provide sustainable, hard and fire safe bedding for rigid top insulation layers as well as insulating the bearing layer in renovation sites. The suitable roof slab for flat roof will be chosen based on the product's mechanical properties and thermal conductivity. The compressive stress of PAROC ROS 30g is 30 kPa. The ventilation grooves in the surface of the board are installed upwards during the installation stage. These grooves enable the constant drying of the whole roof construction.