Site powered by Weebly. Managed by Domain.com
Humans realized the value of trying to insulate the walls of their residences as early as Roman times. Generally, it consisted of the use of flax or reeds. When the natural ice industry started building ice storage vaults, they used primarily straw and saw dust. When small ice boxes were built, often they used paper or cellulose. Eventually they used mineral wool made from metal slag, which included sulfur; followed by rock wool, which is limestone heated to 3500 degrees, and made into fiber.
By the early 20th century, cork became the insulation of preference, because of its properties and its “R” value (degree with which its slows heat transfer). It is made from the bark of the cork tree, and while you think of the light fishing bob, large sheets of it are relatively heavy. By the time of the Second World War, it was replaced by spun glass fiber, or fiberglass, pioneered by Owens Corning. In the latter 20th century, fiberglass was replaced by either closed cell polystyrene or foamed polyurethane. The latter has higher “R” value upon manufacture, but tends to deteriorate quicker then closed cell polystyrene because it is more susceptible to moisture. Moisture is the deadly enemy of insulation because water is a good transferor of heat.