Rigid foam can be cut easily to make proper vents.
You need to get a Home Energy Solutions Audit. This typically involves a blower door test, which measures the air-tightness of your home. It can also help to locate the source of air leaks in the building.
Closed Cell Spray Foam is the most effective solution for insulating a pole barn.
Closed Cell Spray Foam is the best insulation for attic space. It has the highest R-value (R-6.2) of any home insulation material. It will not absorb water and will not lose R-value. Still, there are many effective ways to insulate an attic.
It is time to change insulation when old insulation becomes visibly dirty, malodorous, or shows signs of physical damage or infestation by pests.