What does Unfaced Insulation lack?

Unfaced insulation lacks a backing layer, which is a defining characteristic of this type of insulation material. The absence of a backing layer means that unfaced insulation does not have the additional protective or moisture-resistant layer that faced insulation typically includes. This backing layer serves multiple purposes including providing a barrier against moisture and acting as an air seal. The insulation itself is still effective in providing thermal resistance; however, without the backing, it may require additional attention in areas where moisture control is critical, such as basements or exterior walls, to ensure that it performs optimally and does not allow condensation to form.