I just got my report back just now. From the blower door test, my air leakage, on my 1969 split level home, was determined to be 4350 cfm50. It states that standards indicate that the building air tightness limit is 1748 cfm50. thus I am 149% greater than the limit.

What is proposed is to spray my attic rafters with open cell foam, product is not Icynene. I am awaiting info with the foam info. It is to be sprayed 6″ on the rafters as well as the gable walls.

I had brought up that everything I have read has been to put closed cell foam on the rafters vs. open cell. Maybe I should pose the question to BASF since they make both as you said. I have ridge vents that would have to be sealed and an attic fan that would need to be removed in the upper attic. I also have read many people who have retrofitted foam (Both open and closed) that there is an odor that lingers, since the air is trapped in the attic with no airflow to dissipate. I did bring up the idea of leaving the gable vents in place to let the attic air out and then seal it up in a week or so once its fully aired out. I am pretty sure both open cel and closed cel foam has to be covered with wither drywall or a spray coating for fire resistance if the attic is used for storage or has mechanical equip.
Just want to make sure that open cell is right for this application.

Maybe it just happens to be sitting in some very prime soil that’s loaded with natural fertilizers!!!