I am siding my house and have purchased exterior 2 inch thick rockwool in 8 pound compression rating.  I would like to install vinyl siding over this.  Is this ok without furring strips?  I purchased the rockwool before I realized I may need furring strips.  Adding them would add alot of cost and time I don’t have.  I was going to buck windows out with lumber and was considering bucking out all outside corners with lumber as I know this is probably where the rockwool is the weakest.  Has anyone put vinyl siding over rockwool without furring strips?  I’m really hoping this is a possibility.  I will be using hurricane washers to attach the rockwool.  I would appreciate any advice anyone has.  Also I’m just a homeowner trying to do this myself as I could not find a contractor to take on any work as they are all to busy.