I carry an aluminum ladder on top of my truck and have been annoyed for years by the howling sound produced by the wind rushing over the holes at the ends of the rungs. On a recent job, I was filling gaps in framing with expanding foam. I still had half a can left when I finished up, so I shot a dab into each end of the ladder rungs. All of my subsequent ladder-hauling trips have been in silence.
Richard Tendick, Lakeville, MN