Polyiso on top of blown in insulation

[aturner1973]

Any issues putting polyiso on top of blown in insulation? I removed the rear panel in my RT and there is some insulation blown in and areas without. I am thinking of putting one large sheet on the backside of the panel along with adding some denim insulation in the nook and crannies, but did not want the reflective portion of the polyiso to create an issue when reflecting into the blown in stuff on the van wall.

The polyiso would be thin and provide about an R-3, but trying to help with insulating for hot and cold while getting to areas I can.

Any suggestions would be appreciated.

[booster]

Blown in insulation in a van RV?

[aturner1973]

expanding foam (the yellow stuff in picture). Blown in wrong terminology. Sorry for confusion