Many manufacturers don’t specify fire caulking around factory firestops from what I have found. Maybe someone else can expand on this.
It could be due to expansion and contraction of the metals. (guessing)
I would check with the MFG on the proper installation of this flue fire stop.
I believe any recommendation we make should be carefully checked before we tell the client. The potential for mis-information is huge and could make us look bad and should the client DIY. What happens when it’s wrong?
Does the warranty or service plan get void… “Dam Home inspector told me to do it”…:shock: