Reply by Michigander

I used to work for a company that makes this type of foam. It is regularly routed for application in garage doors and walk in freezers. If you live near a distributor, you might ask for higher density foams. The stuff you routed is probably 25 psi. You can buy higher densities to 100 psi , which is very rigid. Make sure you get either Owens Corning (pink) or Dow (blue) XPS foam (extruded polystyrene)
Good Luck,
John