Wood siding needs an air space between its backside and the face of foam sheathing.
Insulation between osb and siding.
Unless you provide a small gap between the exterior face of the osb and the back surface of the foam sheathing to provide for some hygric redistribution.
As a result the siding cups cracks and sheds paint.
If you prefer to use polyiso without a foil facing feel free to do so.
Installing foam board insulation under vinyl siding today more than ever before homes are being built with foam board insulation installed on the outside of the sheathing and under the siding.
Yes closed cell high density foam cavity insulation applied to the inside of osb sheathings that are in turn covered on the exterior with impermeable foam sheathings is risky.
Isobrace osb combines the insulation performance of an expanded polystyrene panel with the rigidity of a 7 16 oriented strand board osb.
Many houses built today have a double wall type of insulation with fiberglass batts fastened between the studs on the inside and rigid foam board over.
Foam is less permeable to water vapor and the back of the siding stays wet as the face of the siding dries.
How to install rigid foam under siding.
Hot sun can overheat wood siding causing it to dry excessively and crack.
This detail is used with both new construction and also with renovation work.