Roofing goo (3)
I believe the answer is:
tar
'roofing goo' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tar that I've seen before include "Liquid from wood, coal" , "Road-dressing for a sailor?" , "Black coat" , "Sticky stuff for a kind of sailor" , "Dark viscous stuff" .)