Insulation under staircase...yellow dust??
One of my tenants at a condo townhouse I have in Hamilton Ontario showed me this yellow dust that was falling from the ceiling. Specifically, the yellow dust was falling in between where the drywall and the joists meet in the attached picture.
Could it be insulation that disintegrated over the years? The townhouse was built in the 1970's...
The yellow dust looks like yellow cornmeal and it was a constant stream of dust that was flowing in between the straight vertical piece of drywall that you see in the attached picture and the joist that it's attached to.
Does anyone know what this yellow dust can be? Any suggestions on next steps?
I welcome any ideas or thoughts.