Known for more than 5,000 years, mastic asphalt is still an ideal permanent flooring solution to this day. Special mixtures of bitumen and minerals are incorporated manually in a hot, liquid state. The mass is almost void-free, so it does not need to be compressed. Mastic asphalt screeds are generally gas-tight and thus have a shielding effect against radon. The surface is viscoplastic and can also be applied to critical subfloors such as old wooden floors or directly on underground floors.