One of the oldest and most versatile construction materials, mastic asphalt is used in building and civil engineering as a sealing and wearing surface. The mix of bitumen and fillers is adapted to the application and applied hot by machine or by hand. Mastic asphalt is generally gas-tight and protects against radon. It can be installed on critical substrates such as old wooden floors or directly on waterproofing layers. After about six hours of cooling, the surface is fully usable.