They are made in different sizes according to the job's requirements. Most have sheathing such as OSB for facings. XEPS and urethane foam use CFC's or HCFC's as blowing agents. MEPS does not use any ozone-depleting chemicals. For credit from the Green Builder Program for this option, MEPS insulation or an alternative that has no ozone-depleting chemicals must be used.
Foam insulation can attract insects.
Some companies use borates as an insect barrier in the foam insulation. This is a preferred strategy for protecting the panels. Borates are also topically applied to the facings by some companies. Structural grade adhesives should be used to bind the facings to the foam core. Use the manufacturer warranty as a gauge of the quality of the product.