Built-up roofing systems have been a staple roofing system for institutional and commercial facilities for decades. Property managers and architects have specified Built-up roofing systems because of their flexability and durability. Asphalt and Coal Tar Built-up roof systems consist of 3 or 4 plies of roofing felt mopped together with either Asphalt or Coal Tar Pitch over the roof deck or roof insulation. Gravel or Coatings can be installed over the ply felts to suit the customers needs. Asphalt and Coal Tar built-up systems are two of the oldest and proven time tested roofing systems in the roofing industry.