Methods of re-coating and re-covering bitumen-based built-up roofing membranes

A method of re-coating a bitumen-based built-up roofing membrane which comprises the steps of:

• (A) removing loose mineral aggregate, if any, from the surface of an existing roofing membrane,
• (B) cleaning the surface of the existing roofing membrane,
• (C) applying a flood coat over the cleaned surface, and
• (D) embedding a layer of mineral aggregate material into the flood coat wherein said flood coat comprises a coal tar composition comprising:
• (1) from about 80 parts to about 98 parts by weight of coal tar having an overall float test of from about 50 seconds to about 220 seconds,
• (2) from about 2 parts to about 20 parts by weight of coal tar pitch having a softening point of from about 140 to about 160° C., and
• (3) from about 1% to about 20% by weight, based on the total weight of the composition, of an acrylonitrile-butadiene copolymer.

A method of re-coating a built-up roofing membrane having a mineral-surfaced cap sheet which comprises the steps of:

• (A) cleaning the surface of the mineral-surfaced cap sheet of an existing roofing membrane,
• (B) applying a flood coat over the cleaned surface,
• (C) embedding a layer of inert mineral aggregate material into the flood coat wherein said flood coat comprises a coal tar composition comprising:
• (1) from about 80 parts to about 98 parts by weight of coal tar having an overall float test of from about 50 seconds to about 220 seconds,
• (2) from about 2 parts to about 20 parts by weight of coal tar pitch having a softening point of from about 140 to about 160° C., and
• (3) from about 1% to about 20% by weight, based on the total weight of the composition, of an acrylonitrile-butadiene copolymer.