Before revision: A wall that has had cavity wall insulation installed (after construction), with refilled holes highlighted with arrows During construction of new buildings, cavities are often filled with glass fiber wool or mineral wool panels placed between the two leaves (sides) of the wall , but many other building insulation materials offer various advantages and many others are also widely used.
After revision: A wall that has had cavity wall insulation installed (after construction), with refilled holes highlighted with arrows During construction of new buildings, cavities are often partially filled with rigid insulation panels placed between the two leaves (sides) of the wall