Coal Tar Series 200 Spec: incorporates ASTM D227 coal tar saturated organic roofing felt—the Tarred Felt that has helped provide long term durability to roofing systems for over 100 years. Koppers also offers the 200 Series specification with a top ply of Tar-Glas for project surfacing flexibility. The designation is noted by GP (glass ply) following the specification number. This system is suitable for slopes up to 1/4 inch per foot. The Tar-Glas top ply must be applied the same day as the organic felt plies. Koppers Tar-Glas Felts (used in Series 400 Specifications) and Premium Tar-Glas Felts (used in Series 900 Specifications) are manufactured to meet ASTM D 4990 and were developed specifically for use in Koppers Coal Tar BUR Systems.  Return to General Roof Specification Information