Comment We already performed this experiment (Score 1, Interesting) 51
Pitch pans have been used since the nineteen-hundreds in construction to weatherproof roof penetrations. You need some electrical conduit or some such on the roof, esp. a flat commercial roof, you'd build a sheetmetal enclosure and fill it with pitch after extending the conduit through the roof plate.
Some of the pitch always drips through the roof eventually, sticking to everything in sight, but never quite as well as to human clothing and skin. One contractor I knew would'nt allow it on his job sites, referring to it as the black death.