Another dangerous one here! The steel mast here is 16ft long and supports a heavy Televes aerial. Whoever installed it should have used a set of double brackets and considered using a shorter mast (and a better choice of aerial). Instead they have heaved the lot into a single cradle bracket fixed with a single lashing wire. The wind loading has then caused the corner of the chimney to wear away. Someone has tried to "fix" the chimney by coating the damage with this grey stuff. It's never going to work. We recommended the bracket and lashing be replaced ASAP with a set of galvanised double brackets and possibly a shorter mast, but this advice was ignored. I wonder if it's fallen down and seriously injured anyone yet? It's only a matter of time.