Masonry Magazine July 1978 Page. 19
Perlite
Filled Cavities
Conserve Energy.
Heat transmission can be reduced by 50% or more when silicone treated perlite loose fill insulation is poured into the hollow cores of concrete block or cavity type masonry walls. In fact, cavity walls of face brick and tile show a 63% reduction! But that's not all. Silicone treated perlite loose fill insulation is water repellent-indefinitely.
Specs call for a concrete block wall? Perlite loose fill insulation can help too! By filling the core holes with perlite loose fill insulation your fire rating will be doubled to 4 hours and your "U" factor improved by 54%. And you don't have to worry about permanence. Silicone treated perlite is inorganic and rot, vermin and termite proof. And it's non-combustible with its fusion point of 2300°F.
Even a veneer wall of brick and concrete block can show a 52% improvement in insulating value when filled with loose fill perlite. Don't worry about settling - silicone treated perlite supports its own weight in the wall without settling - and it's easy to handle too! Thanks to its countless glass-like cells it's light-weight and easily poured. It's quick - it's inexpensive and it's permanent - the perfect material for insulating masonry walls.
Perlite Institute, Inc.
45 West 45th Street
New York, N.Y. 10036 212-265-2145