A hybrid insulation system involves a combination of different types of insulation, most commonly closed cell spray foam and fiberglass batts. This cost-effective method, often referred to as “flash and batt,” marries the high-performance capabilities of spray foam with the economics of fiberglass, creating a less costly yet still high-performing building enclosure.
Contrary to using fiberglass on its own, the closed cell foam layer offers a moisture barrier (eliminating rodents, mold, etc.) and the less expensive fiberglass is then added to achieve the desired R-value.