Surfacing Time When Koppers tar saturated organic felts are used, the application of Koppers Coal Tar and aggregate surfacing must be done at the time the felts are applied. In periods of hot, dry weather or when morning dew is not expected, the top surfacing may be delayed overnight, however, a glaze coating is required. Contact your Koppers Technical Representative at 1-800-468-9629. When Tar-Glas and Premium Tar-Glas Felts are used, the application of coal tar and aggregate surfacing may be delayed up to fourteen (14) days. Prior to final surfacing, any damage or deficiencies must be repaired with the same amount of plies as the specified completed roof. Any application deficiencies must be corrected prior to top pour and aggregate surfacing. Koppers does not assume responsibility for the performance of roof coatings or other materials not supplied by Koppers.  Return to Application Considerations and Specifications