RECOMMENDED USESACFoam CrossVent has been designed for use over sloped unventilated roof decks. Slopes must be appropriate for the type of roof system specified. The primary purpose of CrossVent is to provide a thermally efficient insulation with uniform cross venting that promotes air circulation required by many shingle manufacturers. CrossVent allows heat to dissipate while providing a nailable surface and efficient insulation in a one-step labor saving process.